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BIOL 4260 Human Evolutionary Anatomy Lecture 14: Shoulder, Arm, Hand Lecture 2: Fossil Record Appendicular Musculature Functions: Stabilizing the pectoral and pelvic girdles Moving the upper and lower limbs Muscular connections between pectoral girdle and axial skeleton and shock absorption Account for roughly 40 percent of the skeletal muscles in the body Two major groups of appendicular muscles: The muscles of the pectoral girdle and upper limbs The muscles of the pelvic girdle and lower limbs Muscles of the Pectoral Girdle and Upper Limbs Muscle groups: Muscles that stabilize the pectoral girdle (scapula/clavicle) Muscles that move the humerus (arm) Muscles that move the forearm and hand Muscles that move the hand and fingers Anterior Muscles that stabilize the pectoral girdle Pectoralis Minor Serratus anterior Pectoralis minor Subclavis Posterior Muscles that stabilize the pectoral girdle 5 Posterior Muscles stabilize the pectoral girdle Posterior group Trapezius Posterior group Rhomboid major Rhomboid minor 6 Muscles that stabilize the pectoral girdle Posterior group Levator Scapulae 7 Summary : 8 Muscles That Move the Humerus Anterior view (usually insert on humerus): Coracobrachialis Deltoid Pectoralis major Biceps brachii (short head and long head). DOES NOT insert on humerus Subscapularis SUPERFICIAL DEEP Clavicle Sternum Ribs (cut) Deltoid Subscapularis Pectoralis major Coracobrachialis Teres major Biceps brachii, short head Biceps brachii, long head T12 Anterior view Pectoralis major 11 Muscles That Move the Humerus Posterior view (usually insert on humerus) Supraspinatus Deltoid Infraspinatus Teres Major Teres Minor Triceps brachii (long head). Does NOT insert on humerus Lattisimus Dorsi SUPERFICIAL DEEP Vertebra T1 Supraspinatus Infraspinatus Supraspinatus Deltoid Teres minor Teres major Triceps brachii, long head Latissimus dorsi Triceps brachii, lateral head Thoracolumbar fascia Posterior view 14 Summary of Attachments to the Scapula 16 Muscles That Move the Forearm and Hand Most of these muscles originate on the humerus and insert upon the forearm and wrist Exceptions include: Long head of triceps brachii -originates on the infraglenoid tubercle of scapula and inserts on the olecranon Long head of biceps brachii - originates on the supraglenoid tubercle of scapula and inserts of the radial tuberosity of the radius Muscles That Move the Forearm and Hand Flexors of the Elbow Biceps brachii: flexes at the elbow and shoulder Brachialis: flexes at the elbow Brachioradialis: flexes at the elbow Biceps brachii Brachialis 19 Muscles That Move the Forearm and Hand Extensors at the Elbow Anconeus: extension at the elbow Triceps brachii Lateral head: extension at the elbow Long head: extension at the elbow and adduction at the shoulder Medial head: extension at the elbow Muscles That Move the Forearm and Hand Pronators and Supinators Pronator quadratus: pronates the forearm Pronator teres (B): pronates the forearm Supinator (A): supinates the forearm Muscles That Move the Wrist, Hand and fingers Flexors of the wrist Flexor carpi radialis: flex and abduct the wrist Flexor carpi ulnaris: flex and adduct the wrist Palmaris longus: flexion at the wrist Coracoid process of scapula Humerus Coracobrachialis Biceps brachii, short head Biceps brachii, long head Triceps brachii, long head Triceps brachii, medial head Brachialis Medial epicondyle of humerus Pronator teres Brachioradialis Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Flexor digitorum superficialis Palmar carpal ligament Pronator quadratus Flexor retinaculum Superficial muscles of the right upper limb, anterior view Extensor carpi radialis longus Anterior view 25 Posterior view Muscles That Move the Wrist, Hand and fingers Extensors of the wrist Extensor carpi radialis longus: extend and abduct at the wrist Extensor carpi radialis brevis: extend and abduct at the wrist Extensor carpi ulnaris: extension and adduction at the wrist 27 Extensor carpi ulnaris 28 Muscles That Move the Hand and Fingers Extrinsic Muscles of the Hand Relatively large muscles that perform flexion and extension at the joints of the fingers Provide strength and crude control of the hand and fingers These muscles are found mostly on the anterior and posterior surfaces of the forearm Their tendons carpus enclosed in sheaths associated with connective tissue thickenings called retinacula Muscles That Move the Hand and Fingers Intrinsic Muscles of the Hand Smaller muscles that provide fine control of hand Responsible for flexion and extension, and abduction and adduction of the fingers at the metacarpophalangeal joints Responsible for opposition and reposition of the thumb These muscles are found mostly in the palm or the back of the hand Extrinsic Muscles of the Hand Flexor muscles Flexor digitorum superficialis: flexion at the wrist and some digits Flexor digitorum profundus: flexion at the wrist and some digits Flexor pollicis longus: flexion of the thumb Tendon of biceps brachii Median nerve Pronator teres (cut) Brachial artery Radius Ulna Brachioradialis (retracted) Flexor carpi ulnaris (retracted) Flexor digitorum superficialis Flexor pollicis longus Flexor digitorum profundus LATERAL MEDIAL Anterior view of the middle layer of muscles. The flexor carpi radialis muscle and palmaris longus muscle have been removed. 33 Supinator Brachialis Cut tendons of flexor digitorum superficialis Flexor digitorum profundus Flexor pollicis longus Pronator quadratus (see Figure 11.8f) LATERAL MEDIAL Anterior view of the deep layer of muscles 35 Extrinsic Muscles of the Hand (continued) Extensor/Abductor Group Abductor pollicis longus: abduction of thumb Extensor digitorum: extension of fingers and wrist Extensor pollicis brevis: extension of thumb, abducts the wrist Extensor indicis: extension and adduction of index finger Extensor digiti minimi: extension of little finger, extension of wrist Summary for extensors of digits 37 Anconeus Extensor digitorum Extensor digiti minimi Tendon of extensor pollicis longus MEDIAL Abductor pollicis longus Extensor pollicis brevis LATERAL Posterior view of the middle layer of muscles Anconeus Supinator Abductor pollicis longus Extensor pollicis longus Extensor indicis Extensor pollicis brevis Ulna Radius Tendon of extensor digiti minimi (cut) Tendon of extensor digitorum (cut) MEDIAL LATERAL Intrinsic Muscles of the Hand Thenar Muscles Adductor pollicis : adducts the thumb Abductor pollicis brevis: abducts the thumb Opponens pollicis: opposition movement of the thumb Flexor pollicis brevis: flex and adduct thumb Hypothenar Muscles Flexor digiti minimi brevis: flex little finger Opponens digiti minimi: brings digits into opposition with the small digit Abductor digiti minimi: abducts little finger Palmaris brevis: moves the skin on the medial side of the palm Intrinsic Muscles of the Hand Midpalmar Muscles Lumbricals: flexion of the digits at metacarpophalangeal joints Dorsal interosseus: abduction of digits 2–4 Palmar interosseus: adduction of digits 2, 4, and 5 42 43 44 45 46 Tendon of flexor digitorum profundus Tendon of flexor digitorum superficialis First dorsal interosseus Synovial sheaths Tendon of flexor pollicis longus Lumbricals Palmar interosseus Adductor pollicis Tendons of flexor digitorum (both profundus and superficialis) Opponens digiti minimi Flexor pollicis brevis Opponens pollicis Flexor digiti minimi brevis Abductor pollicis brevis Palmaris brevis (cut) Tendon of palmaris longus Abductor digiti minimi Flexor retinaculum Tendon of flexor carpi ulnaris Tendon of flexor carpi radialis Anterior (palmar) view Figure 11.11a Intrinsic Muscles, Tendons, and Ligaments of the Hand Tendon of extensor indicis First dorsal interosseus muscle Tendon of extensor digiti minimi Abductor digiti minimi Tendon of extensor pollicis longus Tendon of extensor pollicis brevis Tendon of extensor carpi ulnaris Extensor retinaculum Tendon of extensor carpi radialis longus Tendon of extensor carpi radialis brevis Posterior (dorsal) view