Medical Gross Anatomy: Muscles Table Review

A comprehensive set of vocabulary flashcards covering muscle names, actions, innervations, and clinical notes based on standard Gross Anatomy tables.

Erector spinae

A muscle group composed of three columns—iliocostalis (laterally), longissimus (intermediate), and spinalis (medially)—that extends and laterally bends the trunk, neck, and head; it is segmentally innervated by dorsal primary rami of spinal nerves $C1-S5$.

Transversospinal muscle group

A specific group of deep back muscles consisting of the semispinalis, multifidus, and rotatores.

Suboccipital triangle

An anatomical region formed by the obliquus capitis superior, obliquus capitis inferior, and rectus capitis posterior major muscles.

Splenius

A muscle meaning 'bandage' due to its broad, flat shape; it includes capitis and cervicis portions that extend and laterally bend the neck and head while rotating the head to the same side.

Biceps brachii

A muscle with a short head (coracoid process) and long head (supraglenoid tubercle) that inserts into the radial tuberosity; it flexes the arm and forearm and acts as a powerful supinator; innervated by the musculocutaneous nerve ($C5,6$).

Deltoid

The principal abductor of the arm—supported by the supraspinatus for initiation—innervated by the axillary nerve ($C5,6$) from the posterior cord of the brachial plexus.

D-PAD

A mnemonic for the hand: Dorsal interosseous ABduct (moving digits $2-4$ away from the midline of the 3rd digit).

PA-DAB

A mnemonic for the hand: Palmar interossei ADduct (moving digits $1, 2, 4, 5$ toward the midline of the 3rd digit).

Rotator cuff muscles

A functional group of four muscles including the subscapularis, supraspinatus, infraspinatus, and teres minor.

Anatomic snuffbox

An area bordered laterally by the tendons of abductor pollicis longus and extensor pollicis brevis, and medially by the extensor pollicis longus; the radial artery pulse can be felt here.

Lumbricals (hand)

Muscles arising from the flexor digitorum profundus tendons that flex the metacarpophalangeal joints and extend the interphalangeal joints of digits $2-5$.

Thenar compartment

A group of three muscles in the hand acting on the thumb: abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis.

Hypothenar compartment

A group of three muscles acting on the 5th digit: abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi.

Pectoralis major

A large muscle that flexes, adducts, and medially rotates the arm; its anterior fascia should not be fused to the breast gland, as fusion is a clinical sign of breast disease.

Serratus anterior

Originates from ribs $1-8$ or $9$ and inserts on the medial border of the scapula; innervated by the long thoracic nerve ($C5-C7$); lesions to this nerve cause 'winging' of the scapula.

Triceps brachii

A three-headed muscle consisting of long, lateral, and medial heads that insert into the olecranon process to extend the forearm; innervated by the radial nerve.

Diaphragm

The primary muscle of inspiration that increases thoracic cavity volume; it attaches to the central tendon and is innervated by the phrenic nerve ($C3-C5$).

Cremaster

An extension of the internal abdominal oblique muscle that elevates the testis; its reflex is elicited by stroking the medial thigh.

Dartos

A layer of modified arrector pili fibers in the scrotum and penis (or labium majus and clitoris) that elevates the testis in response to cold.

Rectus abdominis

A muscle originating from the pubis and inserting on the xiphoid process and costal cartilages $5-7$; it flexes the trunk and is contained within the rectus sheath.

Pelvic diaphragm

A support structure formed by the combination of the coccygeus and levator ani muscles.

Levator ani

A multifaceted muscle group consisting of the puborectalis, pubococcygeus, and iliococcygeus.

Hamstring muscles

A group of muscles on the posterior thigh including the biceps femoris (long head), semitendinosus, and semimembranosus; they extend the thigh and flex the leg.

Pes anserinus

A common insertion point on the medial surface of the tibia for the gracilis, sartorius, and semitendinosus muscles.

Quadriceps femoris

A complex of four muscles—rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis—that extends the knee via the patellar ligament.

Sartorius

Known as the 'tailor' muscle (Latin: sartorius), it flexes, abducts, and laterally rotates the thigh, and flexes the leg to achieve a cross-legged seated position.

Tibialis anterior

A muscle in the anterior compartment of the leg that dorsiflexes and inverts the foot; innervated by the deep fibular (peroneal) nerve.

Triceps surae

A term sometimes used to describe the combination of the soleus and the two heads of the gastrocnemius.