FUNCTIONAL HUMAN ANATOMY LAB #7 UPPER EXTREMITY MUSCULATURE

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1 FUNCTIONAL HUMAN ANATOMY LAB #7 UPPER EXTREMITY MUSCULATURE The following tips will help you in naming the muscles of the forearm and hand: The Ulna is located on the pinky side of the wrist, the Radius is located on the thumb side of the wrist. This will be maintained regardless of hand position (pronated vs. supinated). The anterior side of the forearm and the palmar side of the hand contain muscles that perform flexion and may have flexor in the name. The posterior side of the forearm and the dorsal side of the hand contain muscles that perform extension and may have extensor in the name. Most muscles in the anterior forearm originate or appear to originate from the medial epicondyle of the Humerus. Most muscles in the posterior forearm originate or appear to originate from the lateral epicondyle of the Humerus. Any muscle that attaches to the 1 st digit (thumb) has Pollicus in the name Any muscle that attaches to the 2 nd digit (index finger) has Indicis in the name Any muscle that attaches to the 5 th digit (pinky finger) has Digiti Minimi in the name Any muscle that attaches to all of the digits (2-5) has Digitorum in the name Radialis muscles perform radial deviation Ulnaris muscles perform ulnar deviation MUSCULATURE: BACK/UPPER EXTREMITY: Latissimus Dorsi may occasionally have some attachment along the inferior angle of the scapula thoracolumbar fascia (spinous processes of inferior 6 thoracic vertebre and all lumbar vertebre, iliac crest) and inferior 3 or 4 ribs floor of interturbicular (bicipital) groove Adduction or extension of the Arm at the Shoulder. Internal rotation of the arm at the shoulder Teres major synergistic with latissimus dorsi posterior surface on inferior angle of scapula medial ridge of interturbicular groove same as Latissimus Dorsi 1

2 Supraspinatus one of 4 rotator cuff muscles; primarily concerned with maintaining the position of the humeral head in the glenoid fossa; counterbalances forces placed on the joint externally and by other muscles acting on the joint. Lab 7 supraspinous fossa of scapula superior facet on greater tubercle of humerus Abduction of the arm at the shoulder. Only effective during the first 80 degrees (approx.) of adduction Infraspinatus one of 4 rotator cuff muscles; primarily concerned with maintaining the position of the humeral head in the glenoid fossa; counterbalances forces placed on the joint externally and by other muscles acting on the joint. infraspinous fossa of scapula middle facet on greater tubercle of humerus External rotation of the arm at the shoulder Teres minor one of 4 rotator cuff muscles; primarily concerned with maintaining the position of the humeral head in the glenoid fossa; counterbalances forces placed on the joint externally and by other muscles acting on the joint. lateral border of scapula inferior facet on greater tubercle of humerus External rotation of the arm at the shoulder Subscapularis one of 4 rotator cuff muscles; primarily concerned with maintaining the position of the humeral head in the glenoid fossa; counterbalances forces placed on the joint externally and by other muscles acting on the joint. subscapular fossa of scalpula lesser tubercle of humerus Internal rotation of the arm at the shoulder 2

3 Deltoid consists of anterior, middle and posterior heads (functional) distal end of the clavical, acromion process of scapula, spine of scapula deltoid tuberosity of humerus Flexion and internal rotation (anterior head), abduction (middle head), extension and hyperextension and external rotation (posterior head) of the arm at the shoulder Pectoralis major consists of clavicular, sternal and abdominal heads (functional) proximal half of clavical, lateral side of manubrium and sternum, medial aspect of inferior border of ribcage lateral ridge of interturbicular groove of humerus Flexion and internal rotation (clavicular head), horizontal adduction and internal rotation (sternal head), flexion from a hyperextended position and internal rotation (abdominal head) of the arm at the shoulder Subclavius exact function unknown, may help to draw the clavical anteriorly ARM: Biceps brachii consists of long and short heads (anatomical); long head is lateral, short head is medial; long head tendon sits in interturbicular groove costochondrial joint of 1st rib inferior surface of distal end of clavical unknown long head: supraglenoid tubercle of scapula short head: corocoid process of scapula both heads joins distally and attach to radial tuberosity; non-functional attachment to brachioradialis Flexion of the arm at the shoulder, flexion of the forearm at the elbow only when the wrist is supinated Coracobrachialis shares proximal attachment with short head of corocoid process of the scapula biceps brachii medial side, approx. 1/3 of the way down humerus Flexion and horizontal adduction of the arm at the shoulder 3

4 Brachialis workhorse of the arm anterior side, body of humerus ulnar tuberosity Flexion of the forearm at the elbow in all wrist positions Triceps brachii consists of long, lateral and medial heads (anatomical); medial head is deep to long and lateral heads long head: infraglenoid tubercle of scapula lateral head: posterior side, body of humerus medial head: posterior side, body of humerus all heads join and attach to olecranon process of ulna Extension and hyperextension of the arm at the shoulder (long head only), extension of the forearm at the elbow (long, lateral and medial heads) Anconeus lateral side, proximal end of ulna Extension of the forearm at the elbow FOREARM: Brachioradialis only anterior forearm muscle that attaches on the lateral side of the humerus; radial artery, vein and nerve emerge under this muscle proximal to lateral side, distal end of radius Flexion of the forearm at the elbow in all wrist positions, although this muscle favors a semiprone or neutral wrist position (palms facing each other) 4

5 Pronator teres medial epicondyle of humerus lateral side, approx. 1/3 of the way down radius Pronation and flexion of the forearm at the elbow Flexor carpi radialis medial epicondyle of humerus base of 2 nd metacarpal Flexion of the forearm at the elbow, flexion of the hand at the wrist, radial deviation of the hand at the wrist Palmaris longus does not have a bony, rigid distal attachment medial epicondyle of humerus flexor retinaculum tightens the flexor retinaculum and subsequently the palmar aponeurosis Flexor digitorum superficialis the median nerve is located under this muscle; note tendon arrangement at fingers medial epicondyle of humerus middle phalanges of digits 2-5 Flexion of the forearm at the elbow, flexion of the hand at the wrist, flexion of the digits (from the middle phalanges) Flexor carpi ulnaris ulnar artery, vein and nerve emerge under this medial epicondyle of humerus muscle base of 5 th metacarpal Flexion of the forearm at the elbow, flexion of the hand at the wrist, ulnar deviation of the hand at the wrist 5

6 Flexor digitorum profundus located deep to flexor digitorum superficialis; note tendon arrangement at fingers anterior side, body of radius and ulna distal phalanges of digits 2-5 Flexion of the hand at the wrist and flexion of the digits (from the distal phalanges) Flexor pollicus longus lateral side, body of ulna distal phalange of pollux Flexion of the hand at the wrist, flexion of the thumb Pronator Quadratus primary pronator of forearm distal end of ulna distal end of radius Pronation Extensor carpi radialis brevis and longus longus is more superficial, brevis is deep; also longus muscles have longer tendons longus: base of 2 nd metacarpal (dorsal side) brevis: base of 3 rd metacarpal (dorsal side) Extension of the forearm at the elbow, extension of the hand at the wrist, radial deviation of the hand at the wrist 6

7 Extensor digitorum distal phalange of 2 nd - 5 th digits Extension of the forearm at the elbow, extension of the hand at the wrist, extension of the digits Extensor digiti minimi located along side extensor digitorum distal phalange of 5 th digit Extension of the 5 th digit (pinky finger) Extensor carpi ulnaris base of 5 th metacarpal (dorsal side) Extension of the forearm at the elbow, extension of the hand at the wrist, ulnar deviation of the hand at the wrist Extensor indicis located deep to extensor digitorum body of ulna distal phalange of 2 nd digit Extension of the hand at the wrist, extension of the 2 nd digit Abductor pollicus longus tendon comprises part of snuff box; shortest of the three pollicus muscles in this area dorsal side, body of radius base of 1 st metacarpal Radial deviation of the hand at the wrist, abduction of the thumb 7

8 Extensor pollicus brevis tendon comprises part of snuff box dorsal side, body of radius base of proximal phalange of pollux Radial deviation of the hand at the wrist, extension of the thumb Extensor pollicus longus tendon comprises part of snuff box; longest of the three pollicus muscles in this area medial side, body of radius base of distal phalange of pollux Radial deviation of the hand at the wrist, extension of the thumb Supinator located deep to most of the muscles attached to the lateral epicondyle of the humerus medial side, approx. 1/3 of the way down radius Supinates The muscles above that operate the digits are extrinsic muscles of the hand (the contractile part of the muscle is located outside of the hand and the tendons extend down into the hand); the muscles below are intrinsic muscles of the hand (the entire muscle is located within the hand) HAND: Palmaris brevis very thin muscle located over the hypothenar eminence and attached to the flexor retinaculum Tightens the flexor retinaculum and subsequently the palmar aponeurosis Abductor pollicus brevis most lateral palm muscle; in the thenar eminence Abduction of the thumb 8

9 Flexor pollicus brevis just medial to adductor pollicus brevis; in the thenar eminence Flexion of the thumb Abductor digiti minimi most medial palm muscle; in the hypothenar eminence Abduction of the 5 th digit Flexor digiti minimi just lateral to abductor digiti minimi; in the hypothenar eminence Flexion of the 5 th digit Opponens deep to the thenar and hypothenar eminence muscles Opposition Adductor pollicus located in between the pollux and 2 nd digit Adduction of the thumb Lumbricals located along side the tendons for flexor digitorum superficialis Flexion of the metacarpals and simultaneous extension/hyperextension of the digits Dorsal/palmar interosseous Located inbetween the metacarpals in the hand Adduction of all of the digits (palmar interosseous) and abduction of all of the digits (dorsal interosseous) 9