Unit 6: Muscles of the Superior limb

Coracobrachialis m. Origin: coracoid process of the scapula. Insertion: medial aspect of the body of the humerus. Action: flex shoulder joint, adduct superior limb at shoulder joint.

the slender muscle which lies on the anteromedial aspect of the proximal half of the brachium.

Palmaris longus m. Origin: medial epicondyle of the humerus. Insertion: carpal flexor retinaculum, carpal ligament, and palmar aponeurosis. Action: flex carpal joint.

the slender muscle belly located just medial to that of the flexor carpi radialis muscle.

Brachioradialis m. Origin: lateral supracondylar crest of the humerus. Insertion: base of styloid process of the radius. Action: flex elbow joint, supinate antebrachium (from pronated position), and pronate antebrachium (from supinated position).

the slender muscle which extends from the distolateral aspect of the brachium to the anterolateral aspect of the antebrachium. A large part of its belly lies within the antebrachium.

Deltoideus (deltoid) m. Origin: acromial extremity of the clavicle, acromion and spine of the scapula. Insertion: deltoid tuberosity of the humerus. Action: flex and extend shoulder joint, rotate brachium (both medially and laterally), abduct superior limb at shoulder joint.

- the muscle which forms the fleshy part of the shoulder region lateral and superior to the shoulder joint.

Bicipital aponeurosis

-is a flat tendinous sheet of the biceps brachii muscle near the elbow that diverges medially from the main tendon and blends into the deep antebrachial fascia.

Infraspinatus m. Origin: infraspinous fossa of the scapula. Insertion: greater tubercle of the humerus. Action: extend shoulder joint, rotate brachium laterally (externally).

-the muscle which occupies the infraspinous fossa of the scapula. The spine of the scapula is a convenient landmark to divide the bellies of the supraspinatus and infraspinatus muscles.

Supraspinatus m. Origin: supraspinous fossa of the scapula. Insertion: greater tubercle of the humerus. Action: abduct superior limb at shoulder joint.

The muscle which occupies the supraspinous fossa of the scapula. It lies superior to the spine of the scapula and his deep to the large trapezius muscle.

Anterior muscles of the antebrachium

These nine muscles occupy the anterior medial aspect of the antebrachium. They are often called the antebrachial flexor muscles because they include to carpal flexors and two digital flexors and two other flexors as well as three antebrachial rotators. Most of them originate on or near the medial epicondyles of the humerus. At the carpus, many of their tendons pass through the carpal canal— found there in by the overlying transversely oriented carpal flexor retinaculum.

Origin (origo)

attachment site of a tendon typically at the proximal or more fixed end of a muscle.*

Flexor carpi radialis m. Origin: medial epicondyle of the humerus. Insertion: anterior aspect of bases of the second and third metacarpal bones. Action: flex carpal joint, abduct manus at carpal joint.

best developed of the carpal flexor muscles and lies near the axis (middle) of the anterior aspect of the antebrachium. By forming a tight fist and flexing the carpal joint, some individuals can make the tendon of insertion of this muscle obvious subcutaneously.

Aponeuroses (aponeuroses)

broad or flat, sheet-like muscle attachment.

Extensor pollicis longus m. Origin: posterior aspect of body of the ulna and antebrachial interosseous membrane. Insertion: dorsal aspect of the distal phalanx of thumb. Action: extend digital joints of thumb, abduct thumb at its metacarpophalangeal joint.

lies deep to other posterior antebrachial muscles throughout much of its length. In the distal antebrachium the long extensor muscle of the thumb. Its belly the tendon angles laterally around the dorsal tubercle of the radius (a small posterior projection near the distal extremity) and then courses across those of the extensor carpi radialis muscles to form the posteromedial border of the "anatomic snuffbox."

Pronator teres m. Origin: medial epicondyle of the humerus and medial side of coronoid process of the ulna. Insertion: lateral side of the middle aspect fo body of the radius Action: probate the manus

medial (at the elbow) to lateral. This muscle has a humeral head and an ulnar head. sided" pronator muscle). It slants across the proximal half of the anterior aspect of the antebrachium from the "round" (in transverse section) pronator muscle (vs. the "four-

Multi-action muscle

muscles that are capable of two, three, or even more potential actions. Skeletal muscles involved in locomotion rarely contract independently. To effect most body movements, several muscles and sometimes several groups of muscles are typically involved.

Extensor pollicis brevis m. membrane. Origin: posterior aspect of the body of radius and antebrachial interosseous membrane Insertion: dorsal surface of the proximal phalanx of thumb. Action: extend metacarpophalangeal joint of thumb, abduct thumb at metacarpophalangeal joint.

of this muscle lies just distal to that tendons are adjacent to one another with that of the extensor pollicis brevis oblique passage across the extensor carpi radialis muscles. In the region of the "anatomic snuffbox," the of the abductor pollicis longus and its tendon parallels the latter's the short extensor muscle of the thumb. The belly muscle posterior (medial) to that of the abductor pollicis longus muscle.

Posterior muscles of the antebrachium

on or near the lateral epicondyle of the oriented carpal extensor retinaculum [retinaculum extensorum]. humerus. At the dorsal aspect of the carpus, all of their an abductor muscle associated with the thumb. Most of them originate extensors (one for the index finger, one for the little finger, and two [long and short] for the thumb) as well as extensors (long and short), one ulnar carpal extensor, one "common" digital extensor, four "special" digital antebrachium. They are often called the antebrachial extensor muscles because they include two radial carpal these nine muscles occupy the posterolateral aspect of the tendons are bound in place by the transversely

Extensor indicis m. Origin: posterior aspect of body of the ulna. Insertion: dorsal aspect of the proximal phalanx of index finger. Action: extend the second metacarpophalangeal joint.

posterior antebrachial muscles and its tendon emerges at the distal antebrachium to course to the second the extensor muscle of the index finger. Its belly is deep to other digit (index finger).

Digital extensor m. Origin: lateral epicondyle of the humerus. Insertion: middle and distal phalanges of digits 2, 3, 4, and 5 Action: extend carpal joint, extend interphalangeal joints of digits 2-5.

the "common" digital extensor muscle, so-called because it and palpate the individual tendons of this muscle as they fan out across the dorsal metacarpus to reach extensor carpi radialis brevis muscle. By forcefully extending your digital sends tendons to digits 2-5. It lies subcutaneously on the posterior antebrachium just medial to the joints you may be able to visualize their respective digits and its tendon is often double.

Deep digital flexor m. Origin: proximal aspect of the ulna. Insertion: base of the distal phalanges of digits 2, 3, 4, and 5. Action: flex carpal joints and digital joints of digits 2-5.

the "deeper" of the two main digital flexor muscles. It lies deep to the superficial digital flexor muscle and other anterior antebrachial muscles.

Pronator quadratus m. Origin: distal, anterior aspect of the body of the ulna. Insertion: distal, anterior aspect of body of the radius. Action: pronate the manus.

the "four-sided" pronator muscle. is located near the distal end of the antebrachium deep to the other anterior antebrachial muscles.

Extensor carpi radialis longus m. metacarpal bone. Origin: lateral supracondylar crest of the humerus. Insertion: dorsal aspect of base of the second metacarpal bone Action: extend carpal joint, abduct manus at the carpal joint.

the "long" radial carpal extensor muscle. It lies adjacent (just posterior) to the belly of the brachioradialis muscle on the lateral aspect of the antebrachium.

Extensor carpi radialis brevis m. bone (styloid process of the third metacarpal bone). Action: extend Origin: lateral epicondyle of the humerus. Insertion: dorsal aspect of base of the third metacarpal carpal joint, Action: extend carpal joint; abduct manus at the carpal joint.

the "short" radial carpal extensor. It lies just medial to its "long" counterpart.

Insertion (terminatio)

the attachment site of a tendon typically at the distal or more mobile end of a muscle belly.*

Belly (venter) of the muscle

the contractile portion (which contains the skeletal muscle tissue). It is attached to other structures by tendons at each end and is sometimes divided into named subparts.

Extensor digiti minimi m. Origin: lateral epicondyle of the humerus Insertion: fuses with tendon of digital extensor distributed to the fifth digit; proximal phalanx of the fifth finger Action: extend carpal joint extend digital joints of digit five

the extensor of the fifth (little) digit. Its slender belly lies medial to that of the digital extensor muscle and its tendon is often double.

Tendon (tendo) of the muscle

the fibrous connective tissue structure found at each end of a skeletal muscle belly. It is the non-contractile part of a muscle that attaches the belly to other structures (a bone, cartilage, or another muscle). Tendons of origin or insertion of multi-headed muscles may be single or multiple as can the origins or insertions of single bellied muscles. Tendons that are band-like or cord-like in general structure are simply called tendons.

Triceps brachii m. Origin: long head - lateral border of the scapula; lateral head - lateral and posterior aspects of the humerus; medial head - medial and posterior aspects of the humerus. Insertion: olecranon of the ulna (all three heads by a common tendon). Action: extend elbow joint, extend shoulder joint (long head), adduct superior limb at shoulder joint (long head).

the large muscle which occupies most of the posterior brachial region. It has three heads:

Teres major m. Origin: inferior angle of the scapula. Insertion: medial border of the intertubercular groove (crest of the lesser tubercle) of the humerus. Action: extend shoulder joint, adduct superior limb at shoulder joint, rotate brachium medially (internally).

the larger of the two teres muscles. It lies inferior to the infraspinatus and teres minor muscles on the posterior aspect of the scapular region.

Abductor pollicis longus m. Origin: posterior aspects of the radial and ulnar bodies. Insertion: lateral side of base of the first carpometacarpal joint. metacarpal bone. Action: extend carpal joints, extend digital joints of digit five

the long abductor muscles. Its tendon of insertion angles muscle of the thumb. The on the posterolateral aspect of the carpus during of the "anatomic snuffbox." This unofficial tendon courses parallel to that of the extensor pollicis brevis distolaterally over those of the extensor carpi radialis muscles to insert belly of this muscle is partly covered by other posterior antebrachial extension/abduction involving the thumb. name is applied to the tendon-bounded depression that forms muscle which forms the anterolateral border on the first metacarpal bone. This

Flexor pollicis longus m. Origin: anterior aspect of the radial body. Insertion: distal phalanx of pollex. Action: flex digital joints of pollex.

the long flexor muscle of the thumb. Its belly lies lateral to the deep digital flexor muscle on the anterior aspect of the antebrachium.

Superficial digital flexor m. Origin: medial epicondyle of the humerus, coronoid process of the ulna, proximal aspect of the radius. Insertion: middle phalanges of digits 2, 3, 4, and 5. Action: flex carpal joint, metacarpophalangeal joints, and proximal interphalangeal joints of digits 2-5.

the more superficial of the two major flexor muscles of the digits. It consists of several parts (a humeroulnar head and a radial head) whose bellies and tendons are closely associated with each other in the antebrachium and then diverge distal to the carpus for distribution to digits 2, 3, 4, and 5. It lies deep and medial to the palmaris longus muscle.

Flexor carpi ulnaris m. Origin: medial epicondyle of the humerus, olecranon and body of the ulna. Insertion: pisiform bone, hamulus of the hamate bone, base of the fifth metacarpal bone. Action: flex carpal joint, adduct manus at carpal joint.

the most medial of the anterior antebrachial muscles. It has two parts (heads) named according to their bone of origin: humeral head and ulnar head. The body of the ulna can be used to separate the flexor carpi ulnaris muscle from the more laterally and posteriorly located extensor carpi ulnaris muscle.

Brachialis m. Origin: anterior aspect of the body of the humerus. Insertion: coronoid process of the ulna. Action: flex elbow joint.

the muscle which lies between the biceps brachii muscle and the anterior border of the humerus.

Subscapularis m. Origin: subscapular fossa. Insertion: lesser tubercle of the humerus. Action: rotate brachium medially (internally).

the muscle which lies deep (anterior) to the scapula in the subscapular fossa. It cannot be seen without removing the limb but it can be studied on a model. This is one of the four muscles forming the infamous rotator cuff of sports medicine. The other three are the supraspinatus, infraspinatus, and teres minor muscles.

Biceps brachii m. Origin: long head - neck of the scapula; short head - coracoid process of the scapula. Insertion: tuberosity of the radius, deep antebrachial fascia via bicipital aponeurosis. Action: flex elbow joint, flex shoulder joint, and supinate antebrachium.

the prominent muscle on the anterior aspect of the brachium. It is the most powerful flexor of the elbow joint and the strongest supinator of the antebrachium. It has two named heads (subdivisions):

Head (caput) of the muscle

the result of the fusion of multiple bellies of a muscle.

Anconeus m. Origin: lateral epicondyle of the humerus. Insertion: olecranon (and adjacent body) of the ulna. Action: extend cubital joint.

the small muscle located on the posterolateral aspect of the cubital region.

Supinator m. Origin: lateral epicondyle of the humerus. Insertion: body of the radius. Action: supinate the manus.

the small rotator muscle located on the anterolateral aspect of the cubital region. Its fibers slant mediodistally.

Teres minor m. Origin: lateral border of the scapula. Insertion: greater tubercle of the humerus. Action: adduct superior limb at shoulder joint, rotate brachium laterally (externally).

the smaller of the two teres muscles. It is a slender muscle that lies immediately inferior to the infraspinatus muscle on the posterior aspect of the scapula.

Action

the stated movement of a skeletal muscle is the potential action produced when a muscle contracts.

Extensor carpi ulnaris m. Origin: lateral epicondyle of the humerus; Insertion: base of the fifth metacarpal bone. Action: extend carpal joint, adduct manus at carpal joint proximal, posterior aspect of body of the ulna.

the ulnar carpal extensor ulna. The latter can be used muscle. This muscle has a carpi ulnaris and the flexor carpi ulnaris as a dividing landmark between the bellies of the extensor humeral head and an ulnar head. It lies adjacent and lateral to the body of the muscles,

Muscles of the Shoulder and Scapula

these seven muscles originate wholly or in part on the scapula and causing flexion, extension, adduction, abduction, and rotation at the shoulder joint. they insert at various loci on the proximal half of the humerus. They move the humerus relative to the scapula

Anterior muscles of the brachium

these three muscles have one action in common: flexion of the cubital joint. Two of them also supinate the antebrachium.

Posterior muscles of the brachium

these two muscles both extend the elbow joint and both insert on the olecranon of the ulna.