Distal Humerus Fractures of the Elbow-OrthoInfo - AAOS Copyright 2016 American Academy of Orthopaedic Surgeons Distal Humerus Fractures of the Elbow A distal humerus fracture is a break in the lower end of the upper arm bone (humerus), one of the three bones that come together to form the elbow joint. A fracture in this area can be very painful and make elbow motion difficult or impossible. Most distal humerus fractures are caused by some type of high-energy event—such as receiving a direct blow to the elbow during a car collision. In an older person who has weaker bones, however, even a minor fall may be enough to cause a fracture. Treatment for a distal humerus fracture usually involves surgery to restore the normal anatomy and motion of the elbow. Anatomy Your elbow is a joint made up of three bones: The humerus (upper arm bone) The radius (forearm bone on the thumb side) The ulna (forearm bone on the pinky side) The elbow joint bends and straightens like a hinge.

It is also important for rotation of the forearm; that is, the ability to turn your hand palm up (like accepting change from a cashier) or palm down (like typing or playing the piano). (Left) The bones of the elbow. The "distal humerus" is the lower end of the humerus (upper arm bone). (Right) The major nerves and ligaments of the elbow are highlighted. The elbow consists of portions of all three bones: The distal humerus is the lower end of the humerus. It forms the upper part of the elbow and is the spool around which the forearm bends and straightens. The radial head is the knobby end of the radius where it meets the elbow. It glides up and down the front of the distal humerus when you bend your arm and rotates around the ulna when you turn your wrist up or down. The olecranon is the part of the ulna that "cups" the lower end of the humerus, creating a hinge for elbow movement. The bony "point" of the olecranon can be easily felt beneath the skin because it is covered by just a thin layer of tissue.

The elbow is held together by its bony architecture, as well as ligaments, tendons, and muscles. Three major nerves cross the elbow joint. Top of page Description It is common for the distal humerus to break into several pieces. This is called a "comminuted fracture." A distal humerus fracture occurs when there is a break anywhere within the distal region (lower end) of the humerus. The bone can crack just slightly or break into many pieces (comminuted fracture). The broken pieces of bone may line up straight or may be far out of place (displaced fracture). In some cases, the bone breaks in such a way that bone fragments stick out through the skin or a wound penetrates down to the bone. This is called an open fracture. Open fractures are particularly serious because, once the skin is broken, infection in both the wound and the bone is more likely to occur. Immediate treatment is required to prevent infection. Distal humerus fractures are uncommon; they account for just about 2 percent of all adult fractures. They can occur on their own, with no other injuries, but can also be a part of a more complex elbow injury.

Distal humerus fractures are most often caused by: Falling directly on the elbow Receiving a direct blow to the elbow from something hard, like a baseball bat or a dashboard or car door during a vehicle collision Falling on an outstretched arm with the elbow held tightly to brace against the fall. In this situation, the ulna (one of the forearm bones) is driven into the distal humerus and this causes it to break. Distal humerus fractures are also sometimes caused by weak or insufficient bone. This is most common in older patients whose bones have become weakened by osteoporosis. In these patients, a fracture may occur even after a minor fall. Top of page Symptoms A distal humerus fracture may be very painful and can prevent you from moving your elbow. Other signs and symptoms of a fracture may include: Swelling Tenderness to the touch Stiffness A feeling of instability in the joint, as if your elbow is going to "pop out" In rare cases, the fractured bone may stick out of the skin (open fracture) Top of page Doctor Examination Most patients with distal humerus fractures will go to an urgent care center or emergency room for initial treatment.

Physical Examination Your doctor will talk with you about your medical history and general health and ask about your symptoms. He or she will then examine your elbow to determine the extent of the injury. During the exam, your doctor will: Check your skin for cuts and lacerations. In severe fractures, bone fragments can break through the skin, increasing the risk of infection. Palpate (feel) all around your elbow to determine if there are any other areas of tenderness. This could indicate other broken bones or injuries, such as a dislocated elbow. Check your pulse at the wrist to ensure that there is good blood flow to your hand and fingers. Check to see that you can move your fingers and wrist, and can feel things with your fingers. In some cases, the ulnar nerve may be injured at the same time the fracture occurs. This can result in weakness and numbness in the ring and small fingers. Although you may have pain only at the elbow, your doctor may also examine your shoulder, upper arm, forearm, wrist, and hand to ensure that you do not have any other injuries. X-rays X-rays provide images of dense structures, such as bone. Your doctor will order x-rays of your elbow to help diagnose your fracture.

Depending on your symptoms, your doctor may also order x-rays of your upper arm, forearm, shoulder, wrist, and/or hand to ensure that you do not have any other injuries. (Left) X-ray of a healthy elbow. (Right) This x-ray shows a distal humerus fracture that is severely out of place (displaced). Top of page Treatment While you are in the emergency room, your doctor will apply a splint (like a cast) to your elbow and give you a sling to help keep your elbow in position. Immediate treatment may also include: Applying ice to reduce pain and swelling Medications to relieve pain Whether or not your fracture requires surgery will then be determined. Some distal humerus fractures can be treated without an operation, but this is rare. Nonsurgical Treatment Nonsurgical treatment may be recommended for stable fractures in which the pieces of bone are not out of place (displaced). It may also be recommended for patients who are at higher risk for surgical complications. For example, patients with severe osteoporosis or other medical conditions may not be able to tolerate surgery. Your doctor will apply a splint or sling to hold the elbow in place during healing.

During the healing process, your doctor will take frequent x-rays to make sure the bone has not shifted out of place. Splints are typically worn for 6 weeks before supervised motion is started. If the fracture shifts out of position during this time, you may need surgery to put the bones back together. (Left) The doctor will apply a splint that runs from near your shoulder all the way to your hand. (Right) An elastic bandage is applied to help keep the splint in place. Surgical Treatment Surgery is usually required for distal humerus fractures in which: The bones have moved out of place (displaced fracture) Pieces of bone have punctured the skin (open fracture) Because of the increased risk of infection, open fractures are scheduled for surgery as soon as possible, usually within hours. Patient are given antibiotics by vein (intravenous) in the emergency room, and may receive a tetanus shot. During surgery, the cuts from the injury and the surfaces of the broken bone are thoroughly cleaned out. The bone will typically be repaired during the same surgery. In some cases, however, open fractures will require more than one surgery. Surgical Procedures External fixation.

For severe open fractures, your doctor may apply an external fixator to hold the bones in place until a second surgery can take place. In this operation, the doctor makes small incisions into the skin and inserts metal pins through the bones. The pins project out of the skin and are attached to carbon fiber bars outside the skin. The external fixator acts as a frame to help hold the elbow in a good position until a second surgery can be performed. It gives damaged skin time to improve before surgery to fix the fracture and may reduce the risk of infection. Open reduction and internal fixation. This is the procedure most often used to treat distal humerus fractures. During the procedure, the bone fragments are first repositioned (reduced) into their normal alignment and then held in place with plates and screws attached to the outside of the bone. Surgical considerations. Depending on the fracture, your doctor may have specific considerations during the repair, including: Ulnar nerve placement. In most cases, your doctor will need to gently move the ulnar nerve to prevent it from being injured during surgery. At the end of the procedure, the nerve will be put back in place. Bone grafting.

If some of the bone has been lost through the wound or is crushed, the fracture may require bone graft to fill the gaps. Bone graft can be taken from a donor (allograft) or from another bone in your own body (autograft)—most often the pelvis. In some cases, an artificial material can be used. Osteotomy. Sometimes, the doctor will cut the tip of the elbow (olecranon) to better see the bone fragments. The cut bone is moved out of the way during fracture repair. After the fracture is fixed, the cut olecranon is put back in its original location and repaired with plates and screws, a single screw, or pins and wire. (Left) Preoperative x-ray shows a displaced distal humerus fracture (arrow). (Right) The fracture has been put back into alignment and held in place with metal screws and plates. Reproduced from Bozorgnia S: Use of 90-90 plating for distal humerus fractures. Orthopaedic Knowledge Online Journal 2015; 13(7). Accessed Oct 2016. Total elbow replacement (arthroplasty).

In some cases, the humerus is so severely damaged that it cannot be fixed properly and needs to be replaced. In an elbow replacement, a metal and plastic implant is attached to the humerus after the broken bits of bone are removed. Another metal and plastic implant is attached to the ulna (forearm bone), and the two implants are connected to form a hinge. These implants may be held in place with bone cement. A patient with an elbow replacement will be not be allowed to lift more than 5 pounds with the affected arm for the rest of his or her life. Because of this, the procedure is typically reserved for patients who are older and do not have to lift heavy objects. (Left) Preoperative x-ray of an elderly patient shows a distal humerus that has fractured into multiple pieces. (Right) The patient's elbow joint has been replaced with metal and plastic implants. Reproduced from Cobb TK, Morrey BF: Total elbow arthroplasty as primary treatment for distal humeral fractures in elderly patients. J Bone Joint Surg Am 1997; 79(6): 826-832. Arthrodesis (fusion).

In a younger, more active patient, a severely damaged humerus may sometimes be treated with arthrodesis rather than total elbow replacement. During arthrodesis, the doctor will apply plates and screws to make the humerus and olecranon grow together or fuse as one bone. Although the patient will lose the ability to bend his or her elbow after fusion, he or she will maintain the ability to rotate the hand and will regain a strong elbow joint. This may be especially important to younger patients or to laborers who work with their arms and hands. Complications of Surgery There are risks associated with all surgery. If your doctor recommends surgery, he or she thinks that the possible benefits outweigh the risks. Infection. There is a risk of infection with any surgery. Your doctor will take specific measures to help prevent infection. Damage to nerves and blood vessels. There is a minor risk of damage to nerves and blood vessels around the elbow. Temporary numbness in the hand, or weakness in the hand and wrist may occur. This is caused by stretching of the ulnar nerve during surgery and may take weeks or months to go away. In rare cases, the ulnar nerve may be injured during surgery, and further surgery may be required to help the nerve recover.

Nonunion. Sometimes, a fracture does not heal. The fracture may pull apart and the screws, plates, or wires may shift or break. This can occur for a number of reasons, including: The patient does not follow directions after surgery. The patient has a health problem, such as diabetes, that slows healing. Smoking or using other tobacco products also slows healing. If the fracture was associated with a cut in the skin (open fracture), healing is often slower. Infections can also slow or prevent healing. If the fracture fails to heal, further surgery may be needed. The Anatomy of the Elbow ##LOC[OK]## ##LOC[Cancel]## The Anatomy of the Elbow The elbow is a hinged joint made up of three bones, the humerus, ulna, and radius. The ends of the bones are covered with cartilage. Cartilage has a rubbery consistency that allows the joints to slide easily against one another and absorb shock. The bones are held together with ligaments that form the joint capsule. The joint capsule is a fluid filled sac that surrounds and lubricates the joint.

The important ligaments of the elbow are the medial collateral ligament (on the inside of the elbow) and the lateral collateral ligament (on the outside of the elbow.) Together these ligaments provide the main source of stability for the elbow, holding the humerus and the ulna tightly together. A third ligament, the annular ligament, holds the radial head tight against the radius. There are tendons in your elbow that attach muscle to bone. The important tendons of the elbow are the biceps tendon, which is attached the biceps muscle on the front of your arm, and the triceps tendon, which attaches the triceps muscle on the back of your arm. The muscles in your forearm cross the elbow and attach to the humerus. The outside (lateral) bump just above the elbow is called the lateral epicondyle. Most of the muscles that straighten the fingers and wrist come together and attach to the medial epicondyle, or the bump on the inside of your arm just above the elbow. These two tendons are important to understand because they are common locations of tendonitis. All of the nerves that travel down the arm pass across the elbow.

Three main nerves begin together at the shoulder the radial nerve, the ulnar nerve and the medial nerve. These nerves are responsible for signaling your muscles to work and to also relay sensations such as touch, pain and temperature. Elbow Joint - Anatomy Pictures and Information Home > Skeletal System > Bones of the Arm and Hand > Elbow Joint Elbow Joint The elbow joint is a complex hinge joint formed between the distal end of the humerus in the upper arm and the proximal ends of the ulna and radius in the forearm. The elbow allows for the flexion and extension of the forearm relative to the upper arm, as well as rotation of the forearm and wrist. The rounded distal end of the humerus is divided into two joint processes – the trochlea on the medial side and the capitulum on the lateral side. The pulley-shaped trochlea forms a tight joint with the trochlear notch of the ulna surrounding it.... Move up/down/left/right: Click compass arrows Rotate image: Click and drag in any direction, anywhere in the frame Identify objects: Click on them in the image Elbow Joint, Posterior (Back) Full Elbow Joint Description [Continued from above] . . .

On the lateral side, the concave end of the head of the radius meets the rounded, convex capitulum to complete the elbow joint. The loose union of the capitulum of the humerus and the head of the radius allows the radius to pivot as well as flex and extend. The pivoting of the radius allows for the supination and pronation of the hand at the wrist. Like all other synovial joints, a thin layer of smooth articular cartilage covers the ends of the bones that form the elbow joint. The joint capsule of the elbow surrounds the joint to provide strength and lubrication to the elbow. Slick synovial fluid produced by the synovial membrane of the joint capsule fills the hollow space between the bones and lubricates the joint to reduce friction and wear. An extensive network of ligaments surrounding the joint capsule helps the elbow joint maintain its stability and resist mechanical stresses. The radial and ulnar collateral ligaments connect and maintain the position of the radius and ulna relative to the epicondyles of the humerus. The annular ligament of the elbow extends from the ulna around the head of the radius to hold the bones of the lower arm together.

These ligaments allow for movement and stretching of the elbow while resisting dislocation of the bones. Being a hinge joint, the only movements allowed by the elbow are flexion and extension of the joint and rotation of the radius. The range of motion of the elbow is limited by the olecranon of the ulna, so that the elbow can only extend to around 180 degrees. Flexion of the elbow is limited only by the compression soft tissues surrounding the joint. Because so many muscles originate or insert near the elbow, it is a common site for injury. One common injury is lateral epicondylitis, also known as tennis elbow, which is an inflammation surrounding the lateral epicondyle of the humerus. Six muscles that control backward movement (extension) of the hand and fingers originate on the lateral epicondyle. Repeated strenuous striking while the muscles are contracted and against force – such as that occurring with the backhand stroke in tennis – causes strain on the tendinous muscle attachments and can produce pain around the epicondyle. Rest for these muscles will usually bring about recovery.

Prepared by Tim Taylor, Anatomy and Physiology Instructor Humerus - Anatomy Pictures and Information Home > Skeletal System > Bones of the Arm and Hand > Humerus Humerus The humerus is the both the largest bone in the arm and the only bone in the upper arm. Many powerful muscles that manipulate the upper arm at the shoulder and the forearm at the elbow are anchored to the humerus. Movement of the humerus is essential to all of the varied activities of the arm, such as throwing, lifting, and writing. At its proximal end, the humerus forms a smooth, spherical structure known as the head of the humerus.... Move up/down/left/right: Click compass arrows Rotate image: Click and drag in any direction, anywhere in the frame Identify objects: Click on them in the image 2D Interactive 3D Rotate & Zoom Change Anatomical System Change View Angle Full Humerus Description [Continued from above] . . . The head of the humerus forms the ball of the ball-and-socket shoulder joint, with the glenoid cavity of the scapula acting as the socket.

The rounded shape of the head of the humerus allows the humerus to move in a complete circle (circumduction) and rotate around its axis at the shoulder joint. Just below the head, the humerus narrows into the anatomical neck of the humerus. Two small processes, the greater and lesser tubercles, extend from the humerus just below the anatomical neck as attachment points for the muscles of the rotator cuff. The humerus narrows below the tubercles again in a region known as the surgical neck before extending toward elbow joint as the body of the humerus. About a third of the way to the elbow, the humerus swells into a small process known as the deltoid tuberosity, which supports the insertion point of the deltoid muscle. Below the deltoid tuberosity, the humerus gradually widens, doubling its width as it approaches the elbow. The distal end of the humerus contains two joint-forming processes known as the capitulum and trochlea. On the medial side of the arm, the trochlea interlocks with the ulna of the forearm to form half of the elbow joint.

On the lateral side of the arm, the convex capitulum forms a loose connection with the concave head of the radius. The shape of the joint between the capitulum and radius allows the forearm and hand to rotate and bend at the elbow while the ulna forms a tight hinge with the trochlea. On the posterior side of the humerus, a small cavity known as the olecranon fossa allows the tip of the ulna, known as the olecranon, to lock into the humerus and prevent the extension of the elbow beyond 180 degrees. The humerus is classified structurally as a long bone because it is considerably longer than it is wide. Like all long bones, the humerus is hollow in the middle of its shaft and is reinforced at the ends by small columns of spongy bone known as trabeculae. Red bone marrow, the tissue that produces new blood cells, is found in the ends of the humerus and supported by the trabeculae. The hollow medullary cavity in the middle of the shaft of the humerus is filled with fatty yellow bone marrow for energy storage.

Compact bone forms the largest and strongest structure in the humerus, surrounding the trabeculae in the ends and the medullary cavity in the shaft. Surrounding the entire bone is the fibrous periosteum layer that provides a thin, yet strong connecting material for the tendons and ligaments that bind the humerus to muscles and other bones. Finally, the ends of the humerus are capped by a thin layer of hyaline known as articular cartilage that acts as a shock absorber in the joints. The adult humerus develops from three individual bones in the fetus: the diaphysis, or central shaft, and two epiphyses that form the end caps of the bone. Between these three bones is a thin layer of hyaline cartilage known as the epiphyseal plate or growth plate. Cartilage in the growth plate grows throughout childhood and adolescence to elongate the humerus and provide for the growth of the arm. The cartilage is replaced by bony tissue so that the humerus increases its length significantly while the growth plate remains relatively thin. Finally, at the end of puberty, the cartilage stops growing and is completely replaced by bone to form a singular, unified humerus.

The region of bone between the epiphysis and diaphysis in the mature humerus is known as the metaphysis. Prepared by Tim Taylor, Anatomy and Physiology Instructor Treatment for elbow and wrist injury, elbow or wrist pain - Virginia Therapy & Fitness Center Best Time To Contact You How can we help you? Thanks! We know you are anxious to get started with your physical therapy! Rest assured a member of our patient care team will be in touch with you shortly. Please contact admin there was an error. Elbow & Wrist The Elbow The bones of the elbow are the humerus (the upper arm bone), the ulna (the larger bone of the forearm on the opposite side of the thumb), and the radius (the smaller bone of the forearm on the same side as the thumb). The elbow itself is essentially a hinge joint, meaning it bends and straightens like a hinge. There is a second joint where the end of the radius (the radial head) meets the humerus. This joint is complicated because the radius has to rotate so that you can turn your hand palm up and palm down. At the same time, it has to slide against the end of the humerus as the elbow bends and straightens.

The joint is even more complex because the radius has to slide against the ulna as it rotates the wrist as well. The end of the radius at the elbow is shaped like a smooth knob with a cup at the end to fit on the end of the humerus. The edges are smooth where it glides against the ulna. The muscles of the forearm cross the elbow and attach to the humerus. The outside, or lateral, bump just above the elbow is called the lateral epicondyle. Most of the muscles that straighten the fingers and wrist all come together in one tendon to attach in this area. The inside, or medial, bump just above the elbow is called the medial epicondyle. Most of the muscles that bend the fingers and wrist all come together in one tendon to attach in this area. These two tendons are important to understand because they are a common location of tendonitis. The main muscles that are important at the elbow are the biceps, the triceps, the wrist extensors (attaching to the lateral epicondyle) and the wrist flexors (attaching to the medial epicondyle).

The Wrist The wrist joint is a very complex joint formed between the ends of the radius and ulna and the carpal bones. It is a joint that connects the arm to the hand. There are 8 carpal bones: Lunate, Triquetrum, Pisiform, Capitate, Trapezium, Trapezoid, Hamate, Scaphoid. Two bones, the scaphoid and the lunate, articulate with the radius and ulna to form the wrist joint. Most of the forearm muscles have a tendon that crosses the wrist joint and attaches in the hand. There are many muscles on the front and back of the forearm that are responsible for flexing and extending our hand. Three nerves pass from the forearm, across the wrist and into the hand. These are the radial nerve, the median nerve and the ulnar nerve. The radial nerve it towards the thumb side and provides sensation to the back of the hand from the thumb to middle finger. The median nerve is involved in carpal tunnel syndrome and supplies sensation to the thumb and next two fingers with sensation on just half of the ring finger. The ulnar nerve in on the pinky side and reaches the other half of the ring finger and the pinky.

Common pain syndromes and injuries related to the shoulder include, but are not limited to: Elbow and Wrist Pain "Golfer’s Elbow" [Medial Epicondylitis] Hand Injury The Elbow Complex The Elbow Complex Visit to read moreï¿½ ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ This months article will be on the elbow and radioulnar joints and their surrounding muscles, tendons and ligaments.ï¿½ To start off I will explain the anatomy of the joint and then give some brief examples off injuries and treatments.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ The elbow complex is made of three bones, three ligaments, two joints and one capsule.ï¿½ The joining (articulation) of the humerus with the ulna and radius is commonly called the elbow joint.ï¿½ The elbow joint is a uniaxial hinge joint that allows only flexion and extension.ï¿½ There is about 145 degrees of flexion measured from the 0-degree position of extension.ï¿½ The 0-degree of extension is when your arm is completely straight.ï¿½ There is no active hyperextension, as you have in the shoulder joint.ï¿½ This motion is blocked by a little bony knob (olecranon process) on the ulna fitting into a small depression (olecranon fossa) on the humerus.ï¿½ Some people may be able to hyperextend a few degrees, but this is do to a laxity of ligaments rather than bony structures.

Basic Anatomy ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ The joint (articulation) between the radius and the ulna is known as the radioulnar joint.ï¿½ These two bones connect with each other at both ends, but only the end associated with the elbow complex will be discussed.ï¿½ At this end the top (head) of the radius pivots within a groove in the ulna (radial notch).ï¿½ This joint is a pivot joint, which is uniaxial, and allows only the turning of your forearm clockwise (supination) and counterclockwise (pronation).ï¿½ Measured from the neutral position, there should be about 90 degrees of supination and 80 degrees of pronation.ï¿½ The neutral position is when your hand is straight up and down, like a karate chop.ï¿½ When pronation or supination occur, the radius moves around the ulna.ï¿½ The ulna does not move.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ ï¿½The three ligaments of the elbow are the medial and lateral collateral ligaments and the annular ligament.ï¿½ The medial collateral ligament is triangular shaped and spans the inside (medial) of the elbow.ï¿½ Medial means towards your body, so the medial side of your elbow, would be the side facing your body.ï¿½ It attaches on a bony knob (medial epicondyle) of the humerus and runs obliquely to the medial sides of the coronoid process and the olecranon process of the ulna, which are the bony knobs your can feel on the bottom half of your elbow.ï¿½ The lateral collateral ligament is also triangular shaped and attaches on the lateral side of your humerus (lateral epicondyle) and on the annular ligament and the lateral side of the ulna.ï¿½ Lateral means away from your body, so the lateral side of your elbow would be the side facing away from your body.ï¿½ These two ligaments provide a great

 deal of medial and lateral stability to the elbow.ï¿½ The annular ligament attaches on the front (anteriorly) and on the back (posteriorly) side of the radial notch of the ulna, encompassing the head of the radius and holding it against the ulna.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ The muscles associated with the elbow complex are the Brachialis, Brachioradialis, Biceps, Triceps, Anoconeus, and the Pronator Teres muscles.ï¿½ I will briefly explain the location and function of these muscles and then move into exercises and injuries.ï¿½ Remember throughout the rest of the article that flexion means to decrease the angle of the joint, and extension means to increase the angle of the joint.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ The Brachialisï¿½ attaches to the bottom half of the humerus on the front side and spans the elbow joint in front (anteriorly) to attach on the ulna (coronoid process and the ulnar tuberosity), and lies underneath the biceps muscle.ï¿½ Because the muscle has no attachments to the radius, it plays no role in supination or pronation.ï¿½ Sometimes it isï¿½ referred to as the work horse of the elbow, this muscle is a very strong elbow flexor.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ The Bicep muscle has two heads, a long and a short head.ï¿½ Both heads arise from the scapula.ï¿½ The long head arises from the top of the shoulder joint (supraglenoid tubercle) and runs over the head of the humerus and out of the joint capsule to descend through the bicipital groove to join with the short head that has come from a bony protrusion on the front of the scapula (coracoid process).ï¿½ Because tendons from both heads cross the shoulder in the front, the bicep assists in shoulder flexion.ï¿½ But its main function is flexion of the elbow joint.ï¿½ After the joining of the two heads, they form a common muscle belly covering the front surface of the arm.ï¿½ The bicep muscle tendon then crosses the elbow to attach onto the radius (radial tuberosity).ï¿½ The bicep muscle also turns the forearm clockwise (supinates), because the tendon crosses the front of the elbow joint and

 attaches onto the radius.ï¿½ Remember that the radius is the bone that moves within the forearm.ï¿½ The bicep muscle is strongest when the elbow is flexed about half way.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ The brachioradialus originates from the lower third of the humerus (lateral supracondylar ridge) and inserts onto theï¿½ bottom portion radius (styloid process).ï¿½ This muscle is quite prominent on the top portion of your forearm near the elbow.ï¿½ Because of its more lateral attachment, it is most effective as an elbow flexor when the forearm is in neutral position.ï¿½ This is because of its vertical line of pull.ï¿½ This muscle initially takes the work load during elbow flexion, until your elbow is bent about a third of the way.ï¿½ Then your biceps start to take more of the load, and as you continue flexing your elbow, your bicep muscle takes most of the load.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ The triceps muscle has three heads and is located on the back side of your arm.ï¿½ The long head comes from the bottom part of you shoulder joint (inferior rim of the glenoid fossa) and descends between the teres minor and teres major muscles to join the other two heads.ï¿½ The lateral head originates on the upper back side of your arm (inferior to the greater tubercle on the posterior humerus).ï¿½ The medial head lies underneath the long and lateral heads and originates below the lateral head on the back (posterior) surface of the humerus.ï¿½ The three heads come together to form a common muscle belly.ï¿½ The triceps tendon crosses the elbow on the back side (posteriorly) to insert onto the ulna (olecranon process).ï¿½ Because it spans the rear of the elbow vertically, it is very effective at elbow extension.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ The anconeus muscle is a very small muscle that attaches beside the much larger triceps muscle.ï¿½ It originates from the hind (posterior) surface of your elbow (lateral epicondyle) and the spans the back side of the elbow and inserts onto the ulna (laterally and inferior to the olecranon process).ï¿½ This muscle plays no significant role in elbow extension.ï¿½ When the anconeus contracts, it pulls on the annular ligament and keeps it from being pinched in the olecranon fossa during elbow extension.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ The last muscle is mostly associated with the radius and ulna.ï¿½ It is the pronator teres muscle.ï¿½ This muscle is only being discussed because of its attachment on the medial side of the humerus (medial epicondyle).ï¿½ This muscle also originates from the ulna (coronoid process).ï¿½ It crosses the elbow joint on the front surface (anterior), and runs diagonally to insert on the lateral surface of the radius at about midpoint.ï¿½ Its function is to turn your forearm counter clockwise (pronation), and is assistive in elbow flexion.

Injuries ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ The elbow joint will be used in most all upper body exercises and movements.ï¿½ A common injury is tendonitis felt on the back of the elbow.ï¿½ Most people assume that this is their tricep tendon.ï¿½ However, in most cases, it is the tendon from the wrist flexor muscles.ï¿½ These sets of muscles originate from the rear side of the elbow (medial epicondyle of the humerus) and insert onto the fingers in different arrangements.ï¿½ During lying triceps extensions (skull crushers), some will allow there wrist to be bent backwards.ï¿½ This will cause stress and chronic pain to the back side of the elbow.ï¿½ While most think it is their elbow hurting, it is in reality the tendons from their hands, due to poor grip.ï¿½ This can be fixed by maintaining a strong grip on the bar and keeping your wrist flexed or stiffened.ï¿½ If you have this injury, and feel pain here during lying tricep curl, stay away from

 exercises for the triceps, when your arm is over your head.ï¿½ If any other exercise causes pain, stay away from it for at least four to six weeks.ï¿½ Use cables or dumbbell kickbacks, while working your triceps.ï¿½ After this period of time your tendon should be healed enough to start back using light weight.ï¿½ Remember to keep a firm and correct grip on the bar.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ Tennis elbow is another common malady affecting many people.ï¿½ This is an overuse syndrome or tendonitis involving the outside region of the elbow (lateral humeral epicondyle).ï¿½ In simple terms it hurts on the back and/or outer side of the elbow.ï¿½ Microscopic tears of these tendons are very common for people in their forties, and it may or may not have come from athletics.ï¿½ You can test yourself by noting any tenderness over the elbow.ï¿½ Also you should be able to elicit tension and pain when the elbow is extended, your forearm is turned counter clockwise (pronate) and the wrist is flexed.ï¿½ If you feel pain when doing this, then you should lay off of any activity that causes pain.ï¿½ Such as throwing motions, some triceps exercises, carrying heavy objects with that arm and anything else that may affect the area.

ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ Tendons in general take a long time to heal, because of the lack of blood flow to the area.ï¿½ Tendons naturally have a low blood supply, so the nutrients it needs for healing doesnï¿½t get there as fast as it would for a muscle.ï¿½ So using light resistance with high repetitions will force blood into the working muscle, and allow more blood flow to get to the injured tendon.ï¿½ Of course you might not be able to use heavy weight anyway, but use super light weight, your not going to go to failure here. ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ If you feel you may have injured an area of your elbow complex, you should have it looked at by a physician or therapist, so they can determine the best way for it to heal. Please visit my site at and let me know if you have any comments or questions about my articles.

Chapter 9: THE ARM AND ELBOW Chapter 9: The arm and elbow Muscles of arm (table 9-1 ) The muscles of the anterior arm are the biceps, coracobrachialis, and brachialis. They are supplied by the musculocutaneous nerve. The triceps is the muscle of the posterior arm, and it is supplied by the radial nerve. The anterior and posterior muscles are separated from each other by lateral and medial intermuscular septa (fig. 9-1 ). The biceps brachii arises from the scapula by two heads. The long, or lateral, head, arising from the supraglenoid tubercle, descends within the capsule of the shoulder joint and lies in the intertubercular groove. The short, or medial, head arises from the coracoid process in common with the coracobrachialis. The bicipital tendons give way to muscular bellies that unite and continue as a readily palpable tendon.

The insertion is into the tuberosity of the radius (its posterior part; hence the biceps can act as a supinator) and the fascia of the forearm (and ultimately the ulna) by means of the bicipital aponeurosis (see fig. 9-4 ). The biceps and brachialis are the chief flexors of the forearm. The origin of the brachialis embraces the insertion of the deltoid. The coracobrachialis is generally pierced by the musculocutaneous nerve. The flexion of the forearm (or the twitch of the muscle without movement) that follows tapping of the tendon of insertion of the biceps is known as the biceps reflex. The reflex center is in segments C5 and 6 of the spinal cord. The triceps brachii forms the bulk of the posterior arm. Its three heads are arranged in two planes (fig. 9-2 ): the long and lateral heads occupy a superficial plane, whereas the medial head is deeper. The radial nerve passes between the long and medial heads and then lies on the humerus under cover of the lateral head. The long head separates the triangular from the quadrangular space and the teres major from the teres minor.

The triceps is the extensor of the forearm and takes part in pushing, throwing, hammering, and shoveling. A subcutaneous bursa over the olecranon and tendon of the triceps may become thickened ("miner's elbow"). The extension of the forearm (or the twitch without movement) that follows tapping of the tendon of insertion of the triceps is known as the triceps reflex. The reflex center is in segments C6 and 7 of the spinal cord. Nerves of arm The muscles of the anterior arm are supplied by the musculocutaneous nerve; the triceps is supplied by the radial nerve (see fig. 9-1 ). The musculocutaneous nerve (from the lateral cord) usually pierces the coracobrachialis and descends between the biceps and brachialis (see fig. 9-1 ) to enter the lateral side of the arm. The musculocutaneous nerve supplies the biceps, coracobrachialis, brachialis, and elbow joint and terminates as the lateral antebrachial cutaneous nerve.

The radial nerve (the continuation of the posterior cord) passes posteriorly with the profunda brachii artery, winds around the humerus (fig. 9-2 ) under cover of the long and lateral heads of the triceps, and descends anteriorly into the cubital fossa, where it lies in a deep groove between the brachioradialis and the brachialis (figs. 9-3 and 9-4 ). At, or just inferior to the level of the lateral epicondyle, the radial nerve divides into superficial and deep branches. The nerve has several cutaneous branches (posterior brachial, lower lateral brachial, posterior antebrachial) and muscular twigs to the triceps, anconeus, brachioradialis, extensor carpi radialis longus and usually brevis, and branches to the elbow joint. The superficial branch is the direct continuation of the radial nerve into the forearm. * The deep branch winds laterally around the radius between the layers of the supinator and continues as the posterior interosseous nerve to the muscles of the posterior forearm. The median and ulnar nerves have no branches in the arm and are in transit to the forearm.

The median nerve, which is originally on the lateral side of the brachial artery, crosses anterior to (occasionally behind) that vessel and then descends on its medial aspect. In the cubital fossa (fig. 9-4B ), it lies deep to the median cubital vein and the bicipital aponeurosis and gives a branch to the elbow joint. It enters the forearm between the heads of the pronator teres. The ulnar nerve, originally medial to the brachial artery, proceeds posteriorward to the posterior aspect of the medial epicondyle. It enters the forearm between the heads of the flexor carpi ulnaris and under a tendonous arch formed between these heads (the cubital tunnel). Arteries of arm At the inferior border of the teres major, i.e., the distal limit of the posterior axillary fold, the axillary becomes the brachial artery (figs. 7-3 and 9-4 ). The brachial artery lies superficially on the medial side of the arm, at first medial to the humerus and then anterior to the bone. Hence the artery can be compressed against the humerus.

The pulsations of the artery can be palpated where it is partly overlapped by the biceps and coracobrachialis. This vessel is used in sphygmomanometry. The brachial artery lies successively on the triceps and brachialis and is crossed (usually anteriorly) by the median nerve. At the elbow the artery lies in the middle of the cubital fossa, between the biceps tendon laterally and the median nerve medially (fig. 9-4B ). It is crossed by the bicipital aponeurosis, which separates it from the median cubital vein. Opposite the neck of the radius, it divides into the radial and ulnar arteries, but variations, including high division (in the upper third of the arm), are common. In addition to muscular and nutrient branches, the brachial artery gives off the profunda brachii artery and one or more ulnar collateral arteries. The profunda brachii crosses posterior to the humerus with the radial nerve and divides into collateral branches on the radial side.

These, together with those on the ulnar side, form an extensive anastomosis around the elbow joint, which is completed inferiorly by recurrent branches derived from the radial and ulnar arteries. The existence of the anastomosis is important; the details of the individual branches are not. Cubital fossa (fig. 9-4 ) The brachioradialis laterally and the pronator teres medially form a V-shaped interval known as the cubital fossa. These muscles, which belong to the forearm, arise from the lateral and medial supracondylar ridges of the humerus, respectively, and descend to the radius. The floor of the fossa is formed by the brachialis and by the supinator laterally. The contents include the biceps tendon, brachial artery, and median nerve, from lateral to medial. The artery usually divides at the apex of the fossa. The radial nerve is in a deep groove between the brachioradialis and brachialis. The fossa is roofed by fascia, strengthened by the bicipital aponeurosis, and crossed by the superficial veins. The median cubital vein is frequently used for intravenous injections and blood transfusions.

Its close relationship to the underlying brachial artery and median nerve should be kept in mind. Joints. Elbow joint. The humerus, radius, and ulna form a hinge joint, situated 2 or 3 cm inferior to the epicondyles (figs. 6-16 , 9-5 , and 9-6 ). The capitulum of the humerus articulates with the upper aspect of the head of the radius (humeroradial joint), and the trochlea of the humerus articulates with the trochlear notch of the ulna (humero-ulnar joint). These two parts of the elbow joint are continuous with each other and share a common cavity with the proximal radio-ulnar joint. Effusions of the elbow joint generally occur posteriorly, as do dislocations, and it is from this aspect that the joint is most easily approached surgically. The capsule is weak ion the anterior and posterior sides but is strengthened on each side by ligaments. The radial collateral ligament extends fan wise from the lateral epicondyle to the annular ligament. The ulnar collateral ligament runs from the medial epicondyle to the coronoid process and the olecranon.

The elbow joint is supplied by adjacent nerves. Proximal Radio-ulnar Joint. The circumference of the head of the radius fits into the radial notch of the ulna to form a pivot joint. It is surrounded by the strong anular ligament, which is attached to the anterior and posterior margins of the notch. In children, the head of the radius may be subluxated through the anular ligament by a sudden jerk on the limb. Some fibers extend from the lower margin of the notch to the neck of the radius (quadrate ligament). The synovial membrane is continuous with that of the elbow joint. Movements at Elbow and Proximal Radioulnar Joints. The elbow is a hinge joint; hence movement is limited to flexion and extension. Owing to the shape of the medial part of the trochlea, however, the supinated forearm makes a "carrying angle" with the arm during extension. The term "supination" is used for the position of the forearm and hand when the palm faces anterior, as in the anatomical position. The term "pronation" is used when the palm faces posterior. These terms are used also for the movements that bring about these positions.

Supination and pronation are considerably more complicated than a mere lateral and medial rotation. The axis of movement extends from the middle of the head of the radius to the lower end of the ulna. Although the head of the radius merely rotates within the annular ligament, its inferior end describes an arc around the lower end of the ulna and carries the hand with it. In pronation, the shafts of the radius and ulna cross each other (the main reason for selecting supination to be the anatomical position). The movements are usually accompanied by rotation of the humerus (minimal when the elbow is flexed), and the ulna does not remain fixed. Supination has been thought to be generally stronger than pronation, and the threads of screws are arranged to take advantage of this (for right-handed people). Flexion is controlled by segments C5 and 6 of the spinal cord, pronation and supination by C6, and extension by C7 and 8. The flexors of the forearm are the brachialis, biceps, and brachioradialis. The extensor is the triceps, particularly the medial head. The pronators are the pronator quadratus and the pronator teres.

The supinators are the supinator and the biceps. QUESTIONS 9-1 What are the two main compartments of the arm? 9-1 The compartments of the arm are the anterior, for the flexors (musculocutaneous nerve), and the posterior, for the extensor (radial nerve). 9-2 What are the chief actions of the biceps brachii? 9-2 The biceps is a flexor and powerful supinator of the forearm. It "puts a corkscrew in and pulls the cork out." 9-3 Which spinal segments are associated with (a) flexion and (b) extension at the elbow? 9-3 C5 and 6 nerves (biceps and brachialis) are involved in flexion, and chiefly C6 and 7 nerves (triceps) are concerned with extension at the elbow. See table 8-4 . 9-4 Where is the ulnar nerve in contact with the humerus? 9-4 The ulnar nerve is in contact with the posterior aspect of the medial epicondyle ("funny bone"). When the nerve is under tension in ulnar neuritis, it is possible surgically to transpose the nerve into the anterior elbow.

9-5 Between which muscles, or heads of muscles, do the radial, median, and ulnar nerves enter the forearm? 9-5 Near the elbow, the radial nerve lies between the brachioradialis and the brachialis. The median nerve enters the forearm between the heads of the pronator teres; the ulnar nerve enters between the heads of the flexor carpi ulnaris. 9-6 Which important structures lie medial to the biceps tendon in the cubital fossa? 9-6 The brachial artery and the median nerve lie medial to the biceps tendon in the cubital fossa. Occasionally the artery and nerve pass under cover of a hook-shaped spur of bone, the supracondylar process, which may project from the humerus above the medial epicondyle and is visible radiographically. 9-7 Under which conditions is subluxation of the head of the radius found? 9-7 In children, a sudden jerk on the limb may cause the head of the radius to be subluxated through the anular ligament. 9-8 Look up the origin of the word cubital.

9-8 The word cubital comes from the Latin cubitus, elbow or forearm, on which the Romans rested in a position called "decubitus." A cubit, or ell, is the distance from the elbow to the fingertips. An L-shaped bow is an elbow. Cf. ankle, the part at an angle. Figure legends Figure 9-1 Horizontal section through the middle of the arm. In A, the nerves and vessels are identified. B, shows the flexor muscles (supplied by the musculocutaneous nerve) anterior and the extensors (supplied by the radial nerve) posterior. B.B., biceps brachii; Br., brachialis. The three heads of the triceps are indicated. Figure 9-2 A, The triangular and quadrangular spaces, separated by the long head of the triceps. The subscapular and posterior circumflex humeral arteries, respectively, pass through these spaces, and the axillary nerve traverses the quadrangular space. The spine of the scapula has been cut. B and C show the superficial and deep planes of the triceps. Figure 9-3 Horizontal sections through the upper and lower parts of the arm.

Figure 9-4 The cubital fossa. A, The superficial nerves and veins. B, The contents of the cubital fossa. Figure 9-5 Schematic sagittal section through the humero-ulnar part of the elbow joint. The width of the joint cavity is exaggerated. Figure 9-6 ligaments of right elbow joint. * There is a small and functionally insignificant branch to the brachialis muscle as well. Jump to: Muscle Anatomy Muscle Anatomy Types of Movement All muscles exert their force by pulling between at least two points of attachment. The movement that results from contraction is called the action of the muscle. Typically, one attachment remains stationary and is called the origin and the other attachment moves and is called the insertion. Almost all muscles cross at least one joint (moveable connection between two bones) and cause an action across that joint. The type of movement that results depends upon the nature of the joint. Common types of movement that result from muscle contraction include: Flexion � A movement that decreases the angle between two bones at the joint. Extension � A movement that increases the angle between two bones at the joint.

However, if the angle goes past 180o (a straight line) in the direction opposite flexion the movement is called hyperextension. Rotation � Rotation is a movement that results in movement of one bone around its longitudinal axis. Abduction � A movement that results in the part moving away from the midline. Adduction � A movement that results in the part moving toward the midline. Special types of movement occur at particular joints and include: Dorsiflexion and plantar flexion � These movements only apply to movements of the foot at the ankle joint. Dorsiflexion is when the foot is raised as when you dig in your heels. Plantar flexion is when you lower your foot as when you lift yourself onto the balls of your feet. Inversion and eversion � These movements also apply only to the feet. Inversion is when you turn your feet inward so that your soles are facing one another. Eversion is when you turn your feet outward so that your soles are facing laterally. Supination and pronation � These movements apply to the forearm. Pronation is rotation of the radius across the ulna that results is your palms facing backwards.

Supination is movement in the opposite direction that uncrosses the radius from the ulna to cause the palms to face forward. Opposition � This movement enables us to be skillful tool users. Opposition is the movement of the tip of the thumb that enables it to touch the tips of the other fingers. Naming Skeletal Muscles Memorization of specific muscles is easier if you have some understanding of how the muscle was named. Conversely, deciphering the significance of a muscle�s name will give you information about the muscle. Muscles are named according to a number of criteria: Direction of muscle fibers A muscle may be given a name based on the direction of muscle fibers, or the muscle as a whole, relative to the longitudinal axis of the muscle, or body part with which the muscle is associated. The term rectus implies that the fibers or muscle is oriented straight with respect to the longitudinal axis. The term oblique means that the orientation is at an angle to the longitudinal axis. Relative size When more than one muscle are in the same location they may be distinguished by their relative size.

These terms include: major for bigger and minor for smaller; maximus for biggest, intermedius for middle and minimus for smallest; longus for longest and brevis for shortest. Location Some muscles are given a name based on the bone they are associated with or the region of the body where they are found. For example, the pectoralis major is found in the chest region and the rectus femoris is found near the femur. Number of origins A muscle that has more than one attachment at locations that do not move, called origins, and only one attachment at the location that does move, called the insertion, is said to have more than one head. The term biceps means two heads; the term triceps means three heads; and the term quadriceps means four heads. Location of the origin and insertion A muscle may be named for their attachment sites. For example, the brachioradialis attaches to the humerus (origin) and the radius (insertion). Shape Many muscles are named according to their shape. For example, deltoid means triangular in shape. Action Muscles are often named for their primary action. For example, flexor, extensor, adductor and abductor are names associated with the action of the muscle.

Gross Anatomy The facial muscles are associated with facial expressions. These muscles include: Frontalis The frontalis muscle lies over the forehead (Latin � frons). Posteriorly, it attaches to an aponeurosis and anteriorly it attaches to the skin of the eyebrows. Contraction of the frontalis wrinkles the forehead and raises the eyebrows. Orbicularis oculi The fibers of the orbicularis oculi encircle the eye. This muscle enables you to close your eyes, squint, blink and wink. Orbicularis oris This is another circular muscle that is found within the lips. It closes the mouth and protrudes the lips. Buccinator This muscle has a name that associates it with a �horn blower�. Its fibers run horizontal in the cheeks and attach to the orbicularis oris. The contraction of this muscle flattens the cheeks as during sucking and whistling or when blowing on a trumpet. The compression of the cheeks also helps to hold food between the teeth during chewing. Zygomaticus This muscle's fibers extend from the cheek bones to the corners of the mouth. Contraction of the zygomaticus raises the corners of the mouth as when smiling.

Chewing Muscles The chewing muscles enable you to chew your food by moving the upper and lower teeth against one another. These muscles include: Masseter The masseter attaches to the zygomatic process of the temporal bone and inserts on the mandible. This muscle elevates the mandible during chewing. Temporalis This muscle, as its name implies, attaches to the flat part of the temporal bone. Its fibers converge to attach to a process on the mandible. This muscle also works with the masseter to elevate the mandible during chewing. Neck Muscles The neck muscles move the head and the shoulder girdle. These muscles include: Platysma The platysma is a broad sheet-like muscle that attaches to the connective tissue of the skin of the upper chest and inserts on the mandible and the skin at the corners of the mouth. Contraction of the muscle depresses the mandible, depresses the corners of the mouth and tightens the skin of the neck. Sternocleidomasdoid The name of this muscle describes its attachments. This is a two headed muscle in which one head attaches to the sternum and the other head attaches the clavicle (cleido).

The two heads fuse and attach to the mastoid process of the temporal bone. When both muscles contract together the head flexes as when bowing the head in prayer. If only one muscle contracts the head turns to the opposite side. Anterior Trunk Muscles Pectoralis major This muscle is a large fan-shaped muscle that covers the upper part of the chest. The muscle inserts on the proximal part of the humerus and acts to adduct and flex the arm. Intercostal muscles The intercostal muscles are found between the ribs (costa). These muscles aid in ventilating the lungs by raising and lowering the ribs during forceful breathing. Muscles of the Abdominal Girdle These muscles support the wall of the abdominal cavity. They also are involved with flexion of the vertebral column. These muscles are: Rectus abdominis The rectus abdominis muscles are a pair of strap-like muscle on either side of the midline that goes through the �belly button�. Lean and well-toned muscles give rise to the ever popular �six pack�. The fibers attach to the rib cage and the pubis of the hip bones.

Contraction causes flexion of the vertebral column and, when the vertebral column is held in position, compression of the abdominal cavity. External oblique The fibers of this muscle attach to the lower eight ribs and spiral downward and medially to attach to the hip bone. This muscle also flexes the spine and compresses the abdomen but in addition it also rotates and laterally flexes the spine. Internal oblique The internal oblique is a muscle that is deep to the external oblique and has fibers that crisscross those of the external oblique. Its actions are similar to those of the external oblique. Transversus abdominis This is the deepest muscle of the abdominal wall and it has fibers that run transversely. Its main action is to compress the abdominal cavity. Posterior Trunk Muscles Trapezius The trapezius muscles are superficial muscles of the neck and upper trunk. Taken together they form a diamond shape. Because of their broad attachments they have a number of actions that include extending the head and elevating, depressing, adducting and stabilizing the scapula. Latissimus dorsi This is another flat, superficial muscle that covers the lower back.

It inserts on the proximal end of the humerus and its primary actions are to extend and adduct the humerus. Because of these actions this muscle is sometimes called the �swimmer�s muscle�. Erector Spinae These muscles are the deep muscles of the back. As the name implies, they are extensors of the back. Spasms of these muscles is a common source of back pain. Upper Limb Muscles Deltoid The deltoid muscles are fleshy, triangular muscles that give the shoulder its round contour. The muscle has origins on the pectoral girdle and inserts on the lateral side of the humerus. The primary action of this muscle is abduction of the humerus but it also contributes to flexion and extension of the humerus and lateral and medial rotation of the humerus at the shoulder joint. Biceps brachii This muscle, as its name implies, has two heads. Both heads have an origin on the scapula and insert on the radius. This muscle acts to flex the forearm at the elbow joint and also supinates the forearm. It forms a noticeable bulge on the anterior side of the arm when it contracts.

Brachialis This muscle lies deep to the biceps and flexes the forearm with the biceps brachii. Brachioradialis This muscle has its origin on the distal part of the humerus and its insertion on the distal part of the radius. Hence its name derives from the origin and insertion. It is a weak flexor of the forearm and the muscle lies mainly in the forearm. Triceps brachii This muscle is responsible for most of the flesh on the posterior side of the arm. It has three heads as the name implies and inserts on the point of the elbow. It is the main extensor of the forearm at the elbow joint. Hip Joint Muscles Gluteus maximus This muscle contributes to most of the flesh of the buttocks. It is a powerful extensor of the thigh. It is used primarily when the hip is already flexed as when rising from a sitting position or climbing up stairs. Gluteus medius The gluteus medius lies underneath the gluteus maximus. This muscle is an abductor of the thigh at the hip joint and steadies the pelvis during walking. The gluteus medius is the preferred muscle for intramuscular injections.

Iliopsoas This muscle is totally hidden from view as its has its origin on the anterior side of the ilium and the lower vertebrae and inserts on the proximal part of the femur. It is the main flexor of the thigh at the hip joint. Adductor Muscles The adductor muscles form the fleshy mass on the medial side of the thigh. As the name implies they adduct the thigh at the hip joint. Knee Joint Muscles Hamstring Muscles The hamstring muscles are a group of three muscles, the biceps femoris, semitendinosus and semimembranosus. These muscle form the fleshy posterior part of the thigh. These muscle are flexors of the leg at the knee joint but also contribute to extension of the thigh at the hip joint. Sartorius This is a thin, strap-like muscle that attaches to the hip bone and crosses the anterior side of the thigh to attach to the medial side of the tibia. It is a weak flexor of the leg at the knee joint but also flexes and laterally rotates the thigh as when crossing the knee. Its name means �tailor� because a tailor would cross his legs while sewing.

Quadriceps femoris This muscle has four heads each with their own name. The rectus femoris attaches to the hip bone and the vastus lateralis, vastus intermedius and vastus medialis attach to the femur. All four heads fuse and insert on the proximal tibial. The patella or knee cap forms in the tendon of this muscle. The quadriceps femoris is a powerful extensor of the leg at the knee joint. The rectus femoris also contributes to flexion of the thigh at the hip joint. Ankle and Foot Muscles Tibialis anterior This muscle is a superficial muscle on the anterior leg. It attaches to the tarsal bones on the medial side of the foot and dorsiflexes and inverts the foot. Extensor digitorum longus The name of this muscle says its action. It is an extensor of the toes (2-5) but also dorsiflexes the foot. Gastrocnemius This muscle has two heads and forms the curved calf of the posterior leg. The gastrocnemius attaches to the distal end of the femur and inserts onto the heel bone by way of the calcaneal (Achilles) tendon.

It is a plantar flexor of the foot but because it crosses the knee joint, also contributes to flexion of the leg at the knee joint. Soleus This muscle lies deep to the gastrocnemius muscle. It attaches to the tibia and joins the gastrocnemius at the calcaneal tendon. It is also a plantar flexor of the foot at the ankle joint. Humeral Condyle Fractures in Dogs and Cats | BluePearl Vet Careers Humeral Condylar Fractures Three bones come together to form the elbow joint: the humerus, radius and ulna. The radius supports 80% of the weight; whereas the ulna supports 20% of the weight. The top of the radius bone is in contact with the outer half of the bottom of the humerus bone (called the lateral humeral condyle) at the level of the elbow joint. Because of this anatomy, the forces that are transmitted through the limb can break off the lateral humeral condyle. Puppies have much softer bones than adults; therefore, more fractures occur in immature dogs. All it can take to sustain this type of fracture is a fall or jump off an elevated surface.

Some adult dogs are also susceptible to developing this type of fracture because their humerus has a soft spot (incomplete ossification). This is potentially caused by a genetic defect; therefore, breeding of affected dogs is not recommended. Breeds that are prone to incomplete ossification of the humerus include pugs, cocker spaniels, Brittney spaniels and occasionally Rottweilers. Surgery Because this type of fracture extends into the elbow joint, surgery is essential. Conservative treatment of such fractures with a splint or cast consistently results in a stiff elbow, which impairs the ability of the pet to use the limb. Surgical treatment of a lateral condylar fracture of the humerus must be done soon after the fracture has occurred for the best possible outcome. Your companion’s surgeon will make an incision to expose the fracture. Next, the bones are positioned together so that they line up perfectly, and a screw and pin are inserted to stabilize the fracture. Results Surgical repair of a lateral humeral condylar fracture is essential for a successful outcome. Surgery offers multiple benefits over other treatments. These include a faster recovery, early use of the limb after surgery, and correct healing of the fracture.

Uncommon complications include infection, failure of the fracture to heal, breakage of the metal screw or pin and arthritis of the elbow joint. The result could be arthritis and lameness. Overall, 85% of patients that receive surgery to correct a humeral condylar fracture have very good limb function after recovery. For more information on this subject, speak to the veterinarian who is treating your pet.

Question: The humerus, paired radius, and ulna come together to form what joint?
Answer: Elbow