Dermatomes, Myotomes, Joints Flashcards
What is a dermatome?
A unilateral area of skin innervated by the nerve fibers of a single spinal nerve that originated from a single spinal cord segment.
Myotome
unilateral muscle mass receiving innervation from the fibers conveyed by a single nerve
landmark dermatomes of C5 – C8, T4 and T10, L5, S1 SENSORY NERVES
C 5 - Shoulder C 6 - Thumb C 7 - Middle finger C 8 - Little finger T 4 - Nipple T 10 - Umbilicus L 1 - Groin L 5 - Medial foot S 1 - Lateral leg/foot S 2,3,4 - Anal area
Spinal Nerves Innervating Groups of Muscles
(Myotomes
Match the muscle groups with the spinal nerves:
Upper extremity abductors (deltoid, biceps brachii)
Forearm flexors (biceps brachii, brachioradialis) forearm pronators (REFLEX HAMMER)
Forearm extensor (triceps brachii), Wrist extensors, Finger extensors (REFLEX HAMMER)
Intrinsic hand muscles
Thigh flexion (iliopsoas)
Leg extension (quadriceps) (knee jerk REFLEX) PATELLAR
Foot dorsiflexors and Toe extensors (anterior tibial muscles)
Foot plantar flexors and Toe flexors (posterior tibial muscles) (Achilles tendon REFLEX)
Anal contraction
C-5
C-5/6
C-7
C-8/T1
L-2
L-3/4
L-4/5
S-1/2
S-2,3,4
What spinal cord segment supplies sensory fibers to the radial (lateral) regions of the hand?
A. C4 *B. C6 C. C8 D. T2 E. T4
What spinal cord segment supplies sensory fibers to the (ulnar) medial regions of the hand?
A. C4 B. C6 *C. C8 D. T2 E. T4
What spinal cord segment supplies sensory fibers to the dorsum of the foot?
A. T10 B. T12 C. L2 *D. L5 E. S1
What spinal cord segment supplies sensory fibers to the lateral side of the foot?
A. T10 B. T12 C. L2 D. L5 *E. S1
What spinal cord segment supplies motor fibers to the biceps (flexor) muscles of the upper extremity?
A. C4 B. C4/C5 *C. C5/C6 D. C7 E. C8
What spinal cord segment supplies motor fibers to the anterior thigh (quadriceps) muscles of the lower extremity?
A. T10 B. T12 to L2 *C. L3/L4 D. L5 to S2 E. S2,3,4
A 21-year-old man is brought to the Emergency Department (ED) from the site of a motor vehicle accident. He is conscious, has facial lacerations, is bleeding from the nose, and has a compound fracture of his humerus. Examination reveals that he is profoundly weak in his left lower extremity, somewhat weak on his left upper extremity, perceives vibration when a tuning fork is applied to his left clavicle, but not to his thumb or below that level. What is the MOST LIKELY location of this lesion?
A.C2 B.C4 *C.C6 D.C8 E.T2
Articulation
where two or more bones come together forming a joint
Synarthrosis
(together joints)
Syndesmosis
fibrous joint Suture (On skull) Interosseous membrane (between Ulna and Radius)
Synchondrosis and Symphysis
cartilaginous joint
– a secondary cartilaginous joint composed of fibrocartilage found between the two pubic bones.
Synostosis
bony joint
- two bones are joined together by bone. The joint may have existed during development and grew as a fibrous (suture) or cartilaginous joint, but was replaced by bone upon cessation of growth. e.g. frontal bones, epiphyseal plate (line)
Define the morphological features of a diarthrodial joint?
SYNOVIAL JOINTS
(moveable joints) or synovial joints
- Synovial space (joint cavity)
- Synovial fluid
- Fibrous capsule
- Synovial membrane or sac
- Articular surface of hyaline cartilage (articular cartilage
Types of synovial or diarthrodial joints
Hinge joints
Ball and socket joints
Synovial tendon sheaths
(serous membranes) consist of an inner layer that is attached to the tendon and is called the visceral layer, and an outer layer that is called the parietal layer. Synovial fluid found within the sac or cavity.
Bursae
Consists of a closed sac or envelope of serous membrane. CONTAINS SYNOVIAL FLUID
Arthritis
inflammation of a joint
Synovitis
inflammation of the synovial membrane of a joint
Bursitis
inflammation of a bursa
