Posterior Muscles Flashcards
Erector Spinae (A. Only)
A = prime mover of back extension (I.D. muscle and action only),
Trapezius (O.I.A.N)
O = occipital bone
ligamentum nuchae
spinous processes of C7-T12
I = spine and acromion of scapula
lateral 1/3 of clavicle
A = stabilizes
elevates
retracts
depresses
rotates scapula forward
N = Accessory Nerve (CN XI)
Spinal Nerves C3-C4
Levator scapulae (O.I.N)
O = transverse processes of C1-C4
I = superior vertebral border of scapula
N = Spinal Nerves C3-C5 (C5 via the dorsal scapular nerve)
Rhomboideus major (O.I.A.N)
O = spinous processes of T2-T5
I = medial border of scapula from spine to inferior angle
A = adducts scapula and performs downward rotation of scapula
N = Spinal Nerve C5 (via dorsal scapular nerve)
Rhomboideus minor (O.I.A.N)
O = spinous processes of C7-T1
I = medial border of scapula, superior to spine of scapula
A = adducts scapula and performs downward rotation of scapula
N = Spinal Nerve C5 (via dorsal scapular nerve)
Teres major (O.I.A.N)
O = inferior angle of scapula
I = intertubercular groove of humerus
A = extension
medial rotation
adduction of arm
N = Subscapular Nerve
Latissimus dorsi (“swimmer’s muscle”) (O.I.A.N)
O = spines of T7-T12 and L1-L5
ribs 8-12
iliac crest
I = intertubercular groove of humerus
A = prime arm extensor
adduction
medial rotation at the shoulder
depresses shoulder
N = Thoracodorsal Nerve (C6-C8)
Supraspinatus (O.I.A.N)
O = supraspinous fossa of scapula
I = greater tubercle of humerus
A = stabilizes shoulder joint
abducts arm
N = Suprascapular Nerve
Infraspinatus (O.I.A.N)
O = infraspinous fossa of scapula
I = greater tubercle of humerus
A = stabilizes shoulder joint
laterally rotates arm
N = Suprascapular Nerve
Teres minor (O.I.A.N)
O = lateral scapular border
I = greater tubercle of humerus
A = stabilizes shoulder joint
laterally rotates arm
N = Axillary Nerve
Subscapularis (O.I.A.N)
O = subscapular fossa of scapula
I = lesser tubercle of humerus
A = stabilizes shoulder joint
prime medial rotator of arm
N = Subscapular Nerve
Triceps brachii (O.I.A.N)
O = long head–infraglenoid tubercle of scapula
lateral head–proximal end of lateral humeral margin
medial head–distal to radial groove on posterior humeral shaft
I = olecranon process of ulna
A = prime extensor of forearm; extends arm
N = Radial Nerve (CN VII)
Anconeus (O.I.A.N)
O = lateral epicondyle of humerus
I = lateral aspect of olecranon process of ulna
A = abduction of ulna during forearm pronation; forearm extensor
N = Radial Nerve (CN VII)
Gluteus maximus (“running muscle”) (O.I.A.N)
O = dorsal ilium
sacrum
coccyx
lumbodorsal fascia
I = gluteal tuberosity of femur and iliotibial tract
A = major thigh extensor; lateral rotation of thigh
N = Inferior Gluteal Nerve
Gluteus medius (“walking muscle”) (O.I.A.N)
O = anterior iliac crest of ilium between posterior and anterior gluteal lines
I = greater trochanter of femur
A = abduction and medial rotation of thigh; steadies pelvis
N = Superior Gluteal Nerve
Gluteus minimus (O.I.A.N)
O = lateral surface of ilium between inferior and anterior gluteal lines
I = greater trochanter of femur
A = abduction and medial rotation of thigh; steadies pelvis
N = Superior Gluteal Nerve
Piriformis (O.I.A.N.)
O = anterolateral surface of sacrum
I = greater trochanter of femur
A = abduction (when thigh flexed) and lateral rotation of thigh
N = Spinal Nerves L5-S2
Superior gemellus (O.I.A.N)
O = ischial spine
I = medial surface of greater trochanter of femur
A = lateral rotation of thigh; abduction (when thigh flexed)
N = Spinal Nerves L5-S1 (nerve to obturator internus)
Obturator internus (O.I.A.)
O = obturator membrane and obturator foramen
I = greater trochanter of femur
A = lateral rotation of thigh
N = Spinal Nerves L5-S1
Inferior gemellus (O.I.A.N.)
O = ischial tuberosity
I = medial surface of greater trochanter of femur
A = lateral rotation of thigh; abduction (when thigh flexed)
N = Spinal Nerves L5-S1 (nerve to quadratus femoris)
Quadratus femoris (O.I.A.N)
O = ischial tuberosity
I = intertrochanteric crest of femur
A = lateral rotation of thigh
N = Spinal Nerves L5-S1
Biceps femoris (O.I.A.N)
O = long head–ischial tuberosity
short head–linea aspera
I = head of fibula and lateral condyle of tibia
A = extension of thigh; flexion and lateral rotation of leg
N = Sciatic Nerve
Semitendinosus (O.I.A.N)
O = ischial tuberosity
I = medial aspect of proximal tibial shaft
A = extension of thigh; flexion and medial rotation of leg
Semimembranosus (O.I.A.N)
O = ischial tuberosity
I = medial condyle of the tibia
A = extension of thigh; flexion and medial rotation of leg
N = Sciatic Nerve
