Triceps brachii muscle - wikipedia Triceps brachii muscle Triceps Brachii Triceps brachii seen from behind. Triceps brachii seen from behind. Three different colors represent three different bundles which compose triceps. Long head. Lateral head. Medial head. Details Origin Long head : infraglenoid tubercle of scapula Lateral head : above the radial sulcus Medial head : below the radial sulcus Insertion Olecranon process of ulna Artery Deep brachial artery Nerve Radial nerve and Axillary nerve Actions Extends forearm, long head extends, adducts arm, Extends shoulder Antagonist Biceps brachii muscle Identifiers Latin Musculus triceps brachii Dorlands / Elsevier m_22 / 12551300 TA A04. 6.02. 019 FMA 37688 Anatomical terms of muscle ( edit on Wikidata ) The triceps brachii muscle ( Latin for `` three - headed muscle of the arm '' ) is a large muscle on the back of the upper limb of many vertebrates. It is the muscle principally responsible for extension of the elbow joint ( straightening of the arm ). Contents 1 Structure 1.1 Innervation 1.2 Variation 2 Function 3 Training 4 Clinical significance 5 History 5.1 Etymology 6 Animals 7 Additional images 8 See also 9 References 10 External links Structure The long head arises from the infraglenoid tubercle of the scapula. It extends distally anterior to the teres minor and posterior to the teres major. Horizontal section of upper arm. Triceps muscle shown in green text The medial head arises proximally from the groove of the radial nerve ; from the dorsal ( back ) surface of the humerus ; from the medial intermuscular septum ; and its distal part also arises from the lateral intermuscular septum. The medial head is mostly covered by the lateral and long heads, and is only visible distally on the humerus. The lateral head arises from the dorsal surface of the humerus, lateral and proximal to the groove of the radial nerve, from the greater tubercle down to the region of the lateral intermuscular septum. Each of the three fascicles has its own motorneuron subnucleus in the motor column in the spinal cord. The medial head is formed predominantly by small type I fibers and motor units, the lateral head of large type IIb fibers and motor units and the long head of a mixture of fiber types and motor units. It has been suggested that each fascicle `` may be considered an independent muscle with specific functional roles. '' The fibers converge to a single tendon to insert onto the olecranon process of the ulna ( though some research indicates that there may be more than one tendon ) and to the posterior wall of the capsule of the elbow joint where bursae ( cushion sacks ) are often found. Parts of the common tendon radiates into the fascia of the forearm and can almost cover the anconeus muscle. Innervation All three heads of the triceps brachii are classically believed to be innervated by the radial nerve. However, a study conducted in 2004 determined that, in 20 cadaveric specimens and 15 surgical dissections on participants, the long head was innervated by a branch of the axillary nerve in all cases. Variation A tendinous arch is frequently the origin of the long head and the tendon of latissimus dorsi. In rare cases, the long head can originate from the lateral margin of the scapula and from the capsule of the shoulder joint. Function The triceps is an extensor muscle of the elbow joint and an antagonist of the biceps and brachialis muscles. It can also fixate the elbow joint when the forearm and hand are used for fine movements, e.g., when writing. It has been suggested that the long head fascicle is employed when sustained force generation is demanded, or when there is a need for a synergistic control of the shoulder and elbow or both. The lateral head is used for movements requiring occasional high - intensity force, while the medial fascicle enables more precise, low - force movements. With its origin on the scapula, the long head also acts on the shoulder joint and is also involved in retroversion and adduction of the arm. Training Triceps training The triceps can be worked through either isolation or compound elbow extension movements and can contract statically to keep the arm straightened against resistance. Isolation movements include cable push - downs, lying triceps extensions and arm extensions behind the back. Examples of compound elbow extension include pressing movements like the push up, bench press, close grip bench press ( flat, incline or decline ), military press and dips. A closer grip targets the triceps more than wider grip movements. Static contraction movements include pullovers, straight - arm pulldowns and bent - over lateral raises, which are also used to build the deltoids and latissimus dorsi. Clinical significance This section needs expansion. You can help by adding to it. ( February 2014 ) The triceps reflex, elicited by hitting the triceps, is often used to test the function of the nerves of the arm. This tests spinal nerves C6 and C7, predominately C7. History Etymology It is sometimes called a three - headed muscle ( Latin literally three - headed, tri - three, and ceps, from caput - head ), because there are three bundles of muscles, each of different origins, joining together at the elbow. Though a similarly named muscle, the triceps surae, is found on the lower leg, the triceps brachii is commonly called the triceps. Historically, the plural form of triceps was tricipites, a form not in general use today ; instead, triceps is both singular and plural ( i.e., when referring to both arms ). Animals In the horse, 84 %, 15 %, and 3 % of the total triceps muscle weight correspond to the long, lateral and medial heads, respectively. Many mammals, such as dogs, cattle, and pigs, have a fourth head, the accessory head. It lies between the lateral and medial heads. In humans, the anconeus is sometimes loosely called `` the fourth head of the triceps brachii ''. Additional images Animation. Close up. Long head. Lateral head. Medial head. Still image. Anterior view. Muscles on the dorsum of the scapula, and the Triceps brachii. Triceps and biceps. Movement of biceps and triceps when arm is flexing See also This article uses anatomical terminology ; for an overview, see Anatomical terminology. References ^ Jump up to : Platzer, Werner ( 2004 ). Color Atlas of Human Anatomy, Vol. 1 : Locomotor System ( 5th ed. ). Thieme. ISBN 3 - 13 - 533305 - 1. ^ Jump up to : Lucas - Osma, AM ; Collazos - Castro, JE. ( 2009 ). `` Compartmentalization in the triceps brachii motoneuron nucleus and its relation to muscle architecture ''. J Comp Neurol. 516 ( 3 ) : 226 -- 39. doi : 10.1002 / cne. 22123. PMID 19598170. Jump up ^ See the article `` Skeletal striated muscle '' for a discussion of type I and type II muscle fibers. Jump up ^ Nigel del a rosa die porte madretis ( 2006 ). `` Surgical anatomy of the triceps brachii tendon : anatomical study and clinical correlation ''. Am J Sports Med. 34 ( 11 ) : 1839 -- 43. doi : 10.1177 / 0363546506288752. PMID 16735585. Jump up ^ Bekler H, Wolfe VM, Rosenwasser MP ( 2009 ). `` A Cadaveric Study of Ulnar Nerve Innervation of the Medial Head of Triceps Brachii ''. Clin Orthop Relat Res. 467 ( 1 ) : 235 -- 238. doi : 10.1007 / s11999 - 008 - 0535 - 6. PMC 2600974. PMID 18850256. Jump up ^ de Se'ze MP ; Rezzouk J ; de Se'ze M ; Uzel M ; Lavignolle B ; Midy D ; Durandeau A ( 2004 ). `` Does the motor branch of the long head of the triceps brachii arise from the radial nerve ? ''. Surg Radiol Anat. 26 ( 6 ) : 459 -- 461. doi : 10.1007 / s00276 - 004 - 0253 - z. PMID 15365769. Jump up ^ https://informatics.med.nyu.edu/modules/pub/neurosurgery/reflexes.html Jump up ^ Watson, JC ; Wilson, AM. ( 2007 ). `` Muscle architecture of biceps brachii, triceps brachii and supraspinatus in the horse ''. J. Anat. 210 ( 1 ) : 32 -- 40. doi : 10.1111 / j. 1469 - 7580.2006. 00669. x. PMC 2100266. PMID 17229281. External links Wikimedia Commons has media related to Triceps brachii muscles. Illustration : upper - body / triceps - brachii from The Department of Radiology at the University of Washington Anatomy photo : 06 : 11 - 0100 at the SUNY Downstate Medical Center Photo at Ithaca College Muscles / TricepsBrachii at exrx.net Muscles of the arm Shoulder deltoid rotator cuff supraspinatus infraspinatus teres minor subscapularis teres major fascia : deltoid fascia supraspinous fascia infraspinous fascia Arm ( compartments ) anterior coracobrachialis biceps brachialis posterior triceps brachii anconeus articularis cubiti fascia axillary sheath axillary fascia brachial fascia intermuscular septa lateral medial other spaces quadrangular space triangular space triangular interval Forearm anterior superficial : pronator teres palmaris longus flexor carpi radialis flexor carpi ulnaris flexor digitorum superficialis deep : pronator quadratus flexor digitorum profundus flexor pollicis longus posterior superficial : mobile wad brachioradialis extensor carpi radialis longus and brevis extensor digitorum extensor digiti minimi extensor carpi ulnaris deep : supinator anatomical snuff box abductor pollicis longus extensor pollicis brevis extensor pollicis longus extensor indicis fascia bicipital aponeurosis common tendons extensor flexor antebrachial fascia other cubital tunnel Hand lateral volar thenar opponens pollicis flexor pollicis brevis abductor pollicis brevis adductor pollicis medial volar hypothenar opponens digiti minimi flexor digiti minimi brevis abductor digiti minimi palmaris brevis intermediate lumbrical interossei dorsal palmar fascia posterior : extensor retinaculum extensor expansion anterior : flexor retinaculum palmar aponeurosis Retrieved from `` https://en.wikipedia.org/w/index.php?title=Triceps_brachii_muscle&oldid=814477522 '' Categories : Elbow extensors Muscles of the upper limb Shoulder extensors Hidden categories : Medicine infobox template using GraySubject or GrayPage Medicine infobox template using Dorlands parameter Articles to be expanded from February 2014 All articles to be expanded Articles using small message boxes Talk Contents About Wikipedia Azərbaycanca Беларуская ( тарашкевіца ) ‎ Български Català Čeština Cymraeg Dansk Deutsch Ελληνικά Español Euskara فارسی Français Galego 한국어 Hrvatski Bahasa Indonesia Italiano עברית Latina Lietuvių Magyar Nederlands 日本 語 Norsk Polski Português Română Русский Simple English Slovenščina Srpskohrvatski / српскохрватски Suomi Svenska Українська 粵語 中文 Edit links This page was last edited on 9 December 2017, at 01 : 42. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: action of the triceps brachii muscle at the elbow includes
Answer: extends, adducts arm