Anatomy Flashcards

Question

Clinical features of musculocutaneous nerve palsy

Answer 1

-Sensory loss: numbness over lateral forearm -Motor deficit: paralysis of anterior compartment of arm with very weak elbow flexion and weak forearm supination. Absent biceps reflex. -Deformity: wasting of the anterior compartment of the arm. The elbow usually held in extension with forearm pronated.

Answer 2

-C5/C6 -Posterior cord -The axillary nerve supplies the “sergeant’s patch” of skin over the lower part of deltoid muscle. -Motor: =Deltoid: abducts, flexes and extends shoulder =Teres minor: externally rotates shoulder, forms part of rotator cuff which stabilises shoulder joint

Answer 3

-Fracture of surgical neck of humerus -Stab wounds to posterior shoulder -Anterior shoulder dislocation -Pressure of crutches on armpits (“crutch palsy”)

Answer 4

-Sensory loss: numbness over “sergeant’s patch” -Motor deficit: paralysis of deltoid leading to very weak shoulder abduction from 15-90°; weak shoulder flexion and extension. Paralysis of teres minor leading to weak shoulder external rotation. -Deformity: wasting of deltoid muscle, making the bones of the shoulder joint very prominent and obvious. The shoulder may appear adducted and internally rotated.

Answer 5

-C5/C6/C7/C8/T1 -Posterior cord -The radial nerve is responsible for the sensory supply to: =Posterior arm and forearm =Lateral ⅔ of dorsum of hand =Proximal dorsal aspect of lateral 3½ fingers (thumb, index, middle and half of ring finger -The radial nerve supplies the triceps in the posterior compartment of the arm. The triceps extends and adducts shoulder and extends elbow. The radial nerve innervates the following muscles in the posterior compartment of the forearm: =Brachioradialis: flexes elbow =Anconeus: extends elbow, stabilises elbow joint =Supinator: supinates forearm =Extensor carpi radialis longus and brevis: extend and abduct wrist =Extensor carpi ulnaris: extends and adducts wrist =Extensor digitorum, extensor pollicis longus and brevis, extensor indicis and extensor digiti minimi: extend thumb and fingers at MCPJs and IPJs =Abductor pollicis longus: abducts thumb

Answer 6

-Sensory loss: numbness of skin over posterior arm, posterior forearm and radial distribution of dorsum of hand -Motor deficit: paralysis of posterior compartment of arm: weak elbow extension paralysis of posterior compartment of forearm: weak wrist extension, weak thumb extension and finger MCPJ extension Finger IPJ extension is still possible due to intact nerve supply to the lumbrical muscles of the hand Absent triceps and supinator reflexes -Deformity: “Wrist drop” deformity at rest and on attempted wrist extension (Figure 2). The patient cannot extend their wrist/fingers, resulting in unopposed wrist flexion. In the classical description of a radial nerve injury, the forearm is also pronated, the fingers are flexed, and the thumb adducted. There may also be wasting of triceps and posterior compartment of forearm.

Answer 7

-C5/C6/C7/C8/T1 -Lateral and medial cords -The median nerve does not supply any sensory innervation to the axilla or upper arm. -In the hand, the median nerve supplies: =Skin over thenar eminence =Lateral ⅔ palm of hand =Palmar aspect of lateral 3½ fingers =Dorsal fingertips of lateral 3½ fingers (thumb, index, middle and half of ring finger) -The median nerve supplies all muscles of anterior compartment of forearm except flexor carpi ulnaris and the medial two parts of flexor digitorum profundus: Pronator teres and pronator quadratus: pronate forearm Flexor carpi radialis: flexes and abducts wrist Palmaris longus: flexes wrist and tenses palmar aponeurosis Flexor digitorum superficialis: flexes fingers at PIPJs Lateral two parts of flexor digitorum profundus: flex index and middle fingers at DIPJs Flexor pollicis longus: flexes thumb at IPJ The median nerve also supplies the intrinsic muscles of hand (LOAF muscles): Lateral two lumbricals: flex MCPJs and extend IPJs of index and middle finger Opponens pollicis: opposes thumb Abductor pollicis brevis: abducts thumb Flexor pollicis brevis: flexes thumb at MCPJ

Answer 8

-Sensory loss: numbness of skin over thenar eminence and median distribution of hand. However, in carpal tunnel syndrome, sensation to the palm is usually preserved due to an intact palmar cutaneous branch. -Motor deficit: Paralysis of most of anterior compartment of forearm: weak forearm pronation, wrist flexion and abduction, and weak finger flexion with preservation of DIPJ flexion at ring and little fingers. Paralysis of thenar eminence: weak pincer grip and overall grip strength, weak thumb opposition. -Deformity: “Hand of benediction” deformity on attempted finger flexion, the patient cannot flex their index or middle fingers, resulting in unopposed extension of those two fingers (Figure 3). They cannot make a fist with all of their fingers. Wasting of anterior compartment of forearm and thenar eminence

Answer 9

-C8/T1 -Medial cord -Skin over hypothenar eminence Medial ⅓ palm of hand Palmar aspect of the medial 1½ fingers Medial ⅓ dorsum of hand Dorsal aspect of medial 1½ fingers (little finger and half of ring finger) -The ulnar nerve innervates two muscles in the anterior compartment of the forearm: Flexor carpi ulnaris: flexes and adducts wrist Medial two parts of flexor digitorum profundus: flex ring and little fingers at DIPJs The ulnar nerve innervates most of the intrinsic muscles of the hand (HILA muscles): Hypothenar eminence: opponens digiti minimi, flexor digiti minimi brevis and abductor digiti minimi: oppose, flex and abduct little finger Interossei: palmar interossei adduct, dorsal interossei abduct Medial two lumbricals: flex MCPJs and extend IPJs of ring and little finger Adductor pollicis: adducts thumb. adductor pollicis is not part of the thenar eminence and actually lies deep beneath it as a separate structure. In addition, the superficial branch of the ulnar nerve innervates palmaris brevis.

Answer 10

Sensory loss: numbness over hypothenar eminence and ulnar distribution of hand Motor deficit: Paralysis of flexor carpi ulnaris: weak wrist flexion and adduction Paralysis of medial two parts of flexor digitorum profundus: weak flexion of ring and little finger DIPJs Paralysis of most of the intrinsic muscles of the hand: weak MCPJ flexion and IPJ extension of ring and little fingers, loss of finger abduction and adduction, loss of opposition of little finger Deformity: “Claw hand” deformity at rest and on attempted finger extension: the patient cannot extend the IPJs of their ring or little fingers, resulting in fixed flexion of the IPJs and hyperextension of the MCPJs of these two fingers (Figure 4). The clawed appearance is most pronounced when the nerve is injured at the wrist, for example by compression in Guyon’s canal, as the function of flexor digitorum profundus will be preserved. A claw hand affecting all four fingers is much less common and is usually due to a lesion of the lower part of brachial plexus, such as Klumpke’s palsy. wasting of hypothenar eminence and intrinsic muscles of hand

Answer 11

patient is noted to have impaired hip extension and lateral rotation. He has difficulty rising from a seat and can't climb stairs

Answer 12

patient develops foot drop following a fibular neck fracture

Answer 13

patient cannot adduct his thigh following an anterior hip dislocation

Answer 14

patient is found to have a positive Trendelenburg sign

Anatomy Flashcards

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