Unit 6: Muscles of the Superior Limb

lateral and posterior aspects of the humerus;

Lateral head of the triceps brachii muscle Origin:

Biceps brachii m. has two named heads (subdivisions):

Long head of the biceps brachii muscle and Short head of the biceps brachii muscle

lateral border of the scapula

Long head of the triceps brachii muscle Origin:

medial and posterior aspects of the humerus.

Medial head of the triceps brachii muscle Origin:

Aponeuroses

broad or flat, sheet-like muscle attachment.

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 (1)

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.

Deep digital flexor m.

the "deeper" of the two main digital flexor muscles. It lies deep to the superficial digital flexor muscle and other anterior antebrachial muscles. The tendons pass through ("split") those of the superficial digital flexor muscle on the anterior aspect of the bodies of proximal phalanges 2-5.

Pronator quadratus m.

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

Pronator teres m.

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

Insertion

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

Triceps brachii m.

the large muscle which occupies most of the posterior brachial region. It has three heads: Long head of the triceps brachii muscle, Medial head of the triceps brachii muscle, and Lateral head of the triceps brachii muscle

Teres major m.

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.

Long head of the biceps brachii muscle

the lateral belly of the biceps brachii muscle. The tendon of origin of the long head occupies the intertubercular groove of the humerus.

Flexor pollicis (pol' i sis) longus m,

the long flexor muscle of the thumb. Functionally it serves as the "deep digital flexor" of the first digit. Its belly lies lateral to the deep digital flexor muscle on the anterior aspect of the antebrachium.

Superficial digital flexor m.

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.

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.

Deltoideus (deltoid) m.

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

Subscapularis m.

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.

Infraspinatus m.

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.

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

Biceps brachii m.

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): Long head of the biceps brachii muscle & the Short head of the biceps brachii muscle

Flexor carpi radialis m.

the radial flexor of the wrist. It is the 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. It courses own the distal antebrachium somewhat lateral to the limb axis and is directed toward the base of the thenar eminence.

Head of the muscle

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

Palmaris longus m.

the slender muscle belly located just medial to that of the flexor carpi radialis muscle. By forming a tight fist and flexing the carpal joint, some individuals can make the tendon of this muscle obvious subcutaneously. It is said to be absent in about 8% of the population and present on one side only in another 4%. It is absent more often on the left and more often in females.

Brachioradialis m.

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.

Coracobrachialis m.

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

Anconeus (ang kõ' në us) m.

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

Teres minor m.

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.

Anterior muscles of the antebrachium

these nine muscles occupy the anteromedial aspect of the antebrachium. They are often called the antebrachial flexor muscles because they include two "carpal" flexors (radial and ulnar), two "digital" flexors (superficial and deep), two "other" flexors (palmaris longus and flexor pollicis longus), as well as three antebrachial rotators. Most of them originate on or near the medial epicondyle of the humerus. At the carpus, many of their tendons pass through the carpal canal - bound therein by the overlying, transversely oriented carpal flexor retinaculum.

Muscles of the Shoulder and Scapula

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

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.

origin and insertion

*Some textbooks use proximal and distal, superior and inferior, and medial and lateral attachments instead of origin and insertion. During all three muscle labs, we will simplify and use

flex digital joints of pollex.

Flexor pollicis (pol' i sis) longus m, Action:

medial epicondyle of the humerus.

Palmaris longus m. Origin:

Origin

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

Belly 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.

Tendon 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.

Short head of the biceps brachii muscle

the medial belly of the biceps brachii muscle.

Brachialis m.

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

acromial extremity of the clavicle, acromion and spine of the scapula.

Deltoideus (deltoid) m. Origin:

flex carpal joint, abduct manus at carpal joint.

Flexor carpi radialis m. Action:

anterior aspect of bases of the second and third metacarpal bones.

Flexor carpi radialis m. Insertion:

medial epicondyle of the humerus.

Flexor carpi radialis m. Origin:

flex carpal joint, adduct manus at carpal joint.

Flexor carpi ulnaris m. Action:

pisiform bone, hamulus of the hamate bone, base of the fifth metacarpal bone.

Flexor carpi ulnaris m. Insertion:

medial epicondyle of the humerus, olecranon and body of the ulna.

Flexor carpi ulnaris m. Origin:

distal phalanx of pollex.

Flexor pollicis (pol' i sis) longus m, Insertion:

anterior aspect of the radial body.

Flexor pollicis (pol' i sis) longus m, Origin:

extend shoulder joint, rotate brachium laterally (externally).

Infraspinatus m. Action:

greater tubercle of the humerus.

Infraspinatus m. Insertion:

infraspinous fossa of the scapula.

Infraspinatus m. Origin:

extend shoulder joint, adduct superior limb at shoulder joint, rotate brachium medially (internally).

Teres major m. Action:

medial border of the intertubercular groove (crest of the lesser tubercle) of the humerus.

Teres major m. Insertion:

inferior angle of the scapula.

Teres major m. Origin:

adduct superior limb at shoulder joint, rotate brachium laterally (externally).

Teres minor m. Action:

greater tubercle of the humerus.

Teres minor m. Insertion:

lateral border of the scapula.

Teres minor m. Origin:

extend elbow joint, extend shoulder joint (long head), adduct superior limb at shoulder joint (long head).

Triceps brachii m. Action:

olecranon of the ulna (all three heads by a common tendon).

Triceps brachii m. Insertion:

flex shoulder joint, adduct superior limb at shoulder joint.

Coracobrachialis m. Action:

medial aspect of the body of the humerus.

Coracobrachialis m. Insertion:

coracoid process of the scapula,

Coracobrachialis m. Origin:

flex carpal joints and digital joints of digits 2-5.

Deep digital flexor m. Action:

base of the distal phalanges of digits 2, 3, 4, and 5.

Deep digital flexor m. Insertion:

proximal aspect of the ulna.

Deep digital flexor m. Origin:

flex and extend shoulder joint, rotate brachium (both medially and laterally), abduct superior limb at shoulder joint.

Deltoideus (deltoid) m. Action:

extend cubital joint.

Anconeus (ang kõ' në us) m. Action:

olecranon (and adjacent body) of the ulna.

Anconeus (ang kõ' në us) m. Insertion:

lateral epicondyle of the humerus.

Anconeus (ang kõ' në us) m. Origin:

carpal flexor retinaculum

At the carpus, many of their tendons pass through the carpal canal - bound therein by the overlying, transversely oriented...

flex elbow joint, flex shoulder joint, and supinate antebrachium.

Bicipital aponeurosis Action:

tuberosity of the radius, deep antebrachial fascia via bicipital aponeurosis.

Bicipital aponeurosis Insertion:

long head - neck of the scapula; short head - coracoid process of the scapula.

Bicipital aponeurosis Origin:

flex elbow joint.

Brachialis m. Action:

coronoid process of the ulna.

Brachialis m. Insertion:

anterior aspect of the body of the humerus.

Brachialis m. Origin:

flex elbow joint, supinate antebrachium (from pronated position), and pronate antebrachium (from supinated position).

Brachioradialis m. Action:

base of styloid process of the radius.

Brachioradialis m. Insertion:

lateral supracondylar crest of the humerus.

Brachioradialis m. Origin:

deltoid tuberosity of the humerus.

Deltoideus (deltoid) m. Insertion:

flex carpal joint.

Palmaris longus m. Action:

carpal flexor retinaculum, carpal ligament, and palmar aponeurosis.

Palmaris longus m. Insertion:

pronate the manus,

Pronator quadratus m. Action:

distal, anterior aspect of body of the radius.

Pronator quadratus m. Insertion:

distal, anterior aspect of the body of the ulna.

Pronator quadratus m. Origin:

pronate the manus.

Pronator teres m. Action:

lateral side of the middle aspect of body of the radius.

Pronator teres m. Insertion:

medial epicondyle of the humerus and medial side of coronoid process of the ulna.

Pronator teres m. Origin:

rotate brachium medially (internally):

Subscapularis m. Action:

lesser tubercle of the humerus.

Subscapularis m. Insertion:

subscapular fossa.

Subscapularis m. Origin:

flex carpal joint, metacarpophalangeal joints, and proximal interphalangeal joints of digits 2-5.

Superficial digital flexor m. Action:

middle phalanges of digits 2, 3, 4, and 5.

Superficial digital flexor m. Insertion:

medial epicondyle of the humerus, coronoid process of the ulna, proximal aspect of the radius.

Superficial digital flexor m. Origin:

Abduct superior limb at shoulder joint.

Supraspinatus m. Action:

greater tubercle of the humerus.

Supraspinatus m. Insertion:

supraspinous fossa of the scapula.

Supraspinatus m. Origin: