Chapter 1. Anatomy Flashcards
1
Q
1. Nutrition to the lumbar intervertebral disc is from the (A) posterior spinal artery (B) internal iliac artery (C) lumbar artery (D) anterior spinal artery (E) abdominal aorta
A
(C) The lumbar arteries supply the vertebrae
at various levels. Each lumbar artery passes
posteriorly around the related vertebra and
supplies branches into the vertebral body. The terminal branches form a plexus of capillaries below each endplate. The disc is a relatively avascular structure. Nutrition to the disc is by diffusion from the endplate capillaries and blood vessels in the outer annulus fibrosus. Passive diffusion of fluids into the proteoglycan matrix is further enhanced by repeated compression of the disc by repeated flexion extension of the spine associated with activities of daily living which pumps fluid in and out of the disc. The abdominal aorta does not provide any direct blood supply to the intervertebral disc.
2
Q
- A65-year-old man presents with symptoms of pain in the cervical region. He also complains of radiation of his pain along the lateral part of his right forearm. He has a magnetic resonance imaging (MRI) of the cervical region with evidence
of a herniated disc between the fifth and
the sixth cervical vertebra. The nerve root that
is most likely compressed is
(A) fourth cervical nerve root
(B) fifth cervical nerve root
(C) sixth cervical nerve root
(D) seventh cervical nerve root
(E) first thoracic nerve root
A
- (C) Disc herniations in the cervical region are relatively less common than the lumbar region. In the cervical region the C5, C6, and C7 intervertebral disc are most susceptible to herniation. The C6 and C7 intervertebral disc herniation is the most common cervical disc herniations. In the cervical region each spinal nerve emerges above the corresponding vertebra. An intervertebral disc protrusion between C5 and C6 will compress
the sixth cervical spinal nerve. There are
seven cervical vertebra and eight cervical spinal nerves. These patients characteristically present with pain in the lower part of the posterior cervical region, shoulder, and in the dermatomal distribution of the affected nerve root.
3
Q
3. The most common presenting symptom of rheumatoid arthritis is (A) pain in the small joints of the hand (B) neck pain (C) knee pain (D) low back pain (E) hip pain
A
- (B) Neck pain is the most common presenting symptom of rheumatoid arthritis (RA). Approximately 50% of the head’s rotation is at the atlantoaxial joint, the rest is at the subaxial cervical spine. The atlantoaxial joint complex is made up of three articulations. The axis articulates with the atlas at the two facet joints laterally and another joint posterior to the odontoid process. A bursa separates the transverse band of the cruciate ligament from the dens. RA affects all three joints. The articulations formed by the uncinate processes, also known as the joint of Luschka, are not true joints and do not have synovial membrane. Hence, they are not
subject to the same changes as seen in RA.
RA is an inflammatory polyarthritis that
typically affects young to middle-aged women.
They present with a joint pain and stiffness in
the hands. Typically the first metacarpophalangeal joint is affected whereas in osteoarthritis the carpometacarpal joint is affected. They have a history for morning stiffness. Almost 80% of these patients have a positive rheumatoid factor.
4
Q
4. The usual site of herniation of a cervical intervertebral disc is (A) posterior (B) lateral (C) posterolateral (D) anterior (E) anterolateral
A
- (C) The uncinate processes are bony protrusions located laterally from the C3 to C7 vertebrae. They prevent the disc from herniating laterally. The posterior longitudinal ligament is the thickest in the cervical region. It is four to five times thicker than in the thoracic or lumbar region. The nucleus pulposus in the cervical disc is present
at birth but by the age of 40 years it practically disappears. The adult disc is desiccated and ligamentous. It is mainly composed of fibrocartilage and hyaline cartilage. After the age of 40 years, a herniated cervical disc is never seen because there is no nucleus pulposus. The most common cervical herniated nucleus pulposus (HNP) occurs at C6 to C7 (50%) and is followed by C5 to C6 (30%).
5
Q
- The carotid tubercle (Chassaignac tubercle) is located at the
(A) transverse process of the C6 vertebra
(B) facet joint of the C5 and C6 vertebra
(C) facet joint of the C6 and C7 vertebra
(D) transverse process of the C7 vertebra
(E) transverse process of the C5 vertebra
A
- (A) The carotid tubercle (Chassaignac tubercle) lies 2.5 cm lateral to the cricoid cartilage. It lies over the transverse process of the C6 vertebra and can be easily palpated anteriorly. The carotid tubercle is an important landmark for stellate ganglion blocks.
6
Q
- The stellate ganglion is located
(A) anterior to the transverse process of the
C6 vertebra
(B) posterior to the subclavian artery
(C) anterior to the transverse process of the
C5 vertebra
(D) anterior to the neck of the first rib and
the transverse process of the C7 vertebra
(E) anterior to the transverse process of the
first thoracic vertbra
A
- (D) The stellate ganglion is the inferior cervical ganglion. The cervicothoracic ganglion is frequently formed by the fusion of the inferior cervical ganglion and the first thoracic ganglion. It is located anteriorly on the neck of the first rib and the transverse process of the C7 vertebra. It is oval in shape and 1” long by 0.5” wide. The ganglion
is bound anteriorly by the subclavian artery,
posteriorly by the prevertebral fascia and the
transverse process, medially by the longus colli muscle, and laterally by the scalene muscle. The classical stellate ganglion block is done one level above the location of the stellate ganglion (it lies at the C7 level and the block is done at the C6 level). Typically the classical stellate ganglion block is performed with the patient supine, however,
immediately after the block the patient is
repositioned to a sitting position. The vertebral
artery travels anteriorly over the stellate ganglion at C7 but at C6 the artery moves posteriorly. Incidence of phrenic nerve block is almost 100%.
7
Q
7. Features of Horner syndrome consist of the following, EXCEPT (A) ptosis (B) anhydrosis (C) miosis (D) enophthalmos (E) mydriasis
A
- (B) Horner syndrome consists of ptosis (drooping of the upper eyelid), miosis, (constriction of the pupil) and enophthalmos (depression of the eyeball into the orbit) only. Anhydrosis, nasal congestion, flushing of the conjunctiva and skin, and increase in temperature of the ipsilateral arm and
hand are not features of Horner syndrome.
The cervical portion of the sympathetic
nervous system extends from the base of the
skull to the neck of the first rib, it then continues as the thoracic part of the sympathetic chain. The cervical sympathetic system consists of the superior,
middle, and inferior ganglia. In most people
the inferior cervical ganglia is fused with the first thoracic ganglia to form the stellate ganglion. It lies over the neck of the first rib and the transverse process of C7, behind the vertebral artery.
8
Q
- A 35-year-old woman with Complex Regional Pain Syndrome type I of the right upper extremity develops miosis, ptosis, and enophthalmos after undergoing a stellate ganglion block. She does not notice any significant pain relief. No significant rise in skin temperature was recorded in the right upper extremity. What is the most likely cause?
(A) Inadequate concentration of the local
anesthetic
(B) Intravascular injection
(C) Subarachnoid block
(D) Anomalous Kuntz nerves
(E) Inadvertent injection of normal saline
A
- (D) The sympathetic supply to the upper extremity is through the grey rami communicantes of C7, C8, and T1 with occasional contributions from C5 and C6. This innervation is through the stellate
ganglion. Blocking the stellate ganglion
would effectively cause a sympathetic denervation of the upper extremity. In some cases the upper extremity maybe supplied by the T2 and T3 grey rami communicantes. These fibers do not pass through the stellate ganglion. These are Kuntz fibers and have been implicated in inadequate relief of sympathetically maintained pain despite a good stellate ganglion block. These fibers can be blocked by a posterior approach.
Successful block of the sympathetic fibers
to the head is indicated by the appearance of
Horner syndrome. Successful block of the sympathetic block of the upper extremity is indicated by a rise in skin temperature, engorgement of veins on the back of the hand, loss of skin conductance response and a negative sweat test. Alternatively, it is conceivable that the patient has sympathetic independent pain.
9
Q
9. The greater occipital nerve is a branch of (A) posterior ramus of C2 (B) posterior ramus of C1 (C) anterior ramus of C1 (D) anterior ramus of C2 (E) trigeminal nerve
A
- (A) The skin over the posterior part of the neck, upper back, posterior part of the scalp up to the vertex is supplied segmentally by the posterior rami of the C2 to C5. The greater occipital nerve is a branch of the posterior of ramus of C2. The lesser occipital nerve is a branch of the posterior ramus of C2 and C3. Headaches due to occipital neuralgia are characterized by either continuous pain or paroxysmal lancinating pain in the distribution of the nerve. The etiology of occipital neuralgia is compression of the C2 nerve root, migraine, or nerve entrapment. An
occipital nerve block maybe performed as a
diagnostic or therapeutic measure. The trigeminal nerve does not contribute to the greater occipital nerve.
10
Q
- A66-year-old woman presents with pain in the posterior cervical region for the last 1 year. It radiates to the right shoulder, lateral upper
arm, and right index finger. She also complains in the medial part of the right scapula and anterior shoulder. On physical examination, she has numbness to the index and middle fingers of the right hand and weakness of the triceps muscle. The most likely cause of her pain is
(A) herniated nucleus pulposus of the C5 to
C6 disc causing compression of the C5
nerve root
(B) herniated nucleus pulposus of the C5 to
C6 disc causing compression of the C6
nerve root
(C) herniated nucleus pulposus of the C6 to
C7 disc causing compression of the C7
nerve root
(D) herniated nucleus pulposus of the C6 to
C7 disc causing compression of the C6
nerve root
(E) muscle spasm
A
- (C) The pattern of pain helps identify the cervical disc causing the most problems. HNP are more common in the lumbar region. The cervical nerve roots exit above the vertebral body of the same segment. The C7 nerve root exits between the C6 to C7 vertebra.
11
Q
- Blood supply to the spinal cord is by
(A) two posterior spinal arteries and two
anterior spinal arteries
(B) two posterior spinal arteries and one
anterior spinal artery
(C) branches of the lumbar arteries
(D) radicularis magna (artery of
Adamkiewicz) and two posterior spinal
arteries
(E) internal iliac arteries
A
- (B) The blood supply to the spinal cord is primarily by three longitudinally running arteries— two posterior spinal arteries and one anterior spinal artery. The anterior spinal artery supplies approximately 80% of the intrinsic spinal cord vasculature.
It is formed by the union of a branch
from the terminal part of each vertebral artery.
It actually consists of longitudinal series of
functionally individual blood vessels with wide
variation in lumen size and anatomic discontinuations. The spinal cord has three major arterial supply regions: C1 to T3 (cervicothoracic region), T3 to T8 (midthoracic region), and T8 to the conus (thoracolumbar region). There is a poor anastomosis between these three regions. As a result the blood flow at the T3 and T8 levels is tenuous. In spinal stenosis, especially in the lower cervical region, the anterior spinal artery may be compressed by a dorsal osteophyte
and a HNP leading to the anterior spinal
syndrome (loss of motor function).
There are two posterior spinal arteries that
arise from the posterior inferior cerebellar
arteries. The three longitudinal arteries are reinforced by “feeder” arteries. They are spinal branches of the cervical, vertebral posterior intercostal, lumbar, and lateral sacral arteries. Approximately six or seven of these contribute to the anterior spinal artery and another six or seven to the posterior spinal arteries, but at different levels. The largest of these arteries is known as the radicularis magna or the artery of Adamkiewicz.
12
Q
12. The most common origin of the artery of Adamkiewicz is (A) between T4 and T6 (B) at T7 (C) between T8 and L3 (D) at L4 (E) at L5
A
- (C) The artery of Adamkiewicz originates on the left between the T8 and L3 level in most cases. This is the largest of the feeder arteries that supplies the anterior spinal artery. The artery of Adamkiewicz enters through an intervertebral foramen between T8 and L3 to supply the lumbar enlargement.
In a small percentage of cases (15%) the
take off is higher at T5. In this case a slender
contribution from the iliac artery enlarges to
compensate for the increased blood flow to the lumbar portion of the cord and the conus.
The cervical portion up to the upper thoracic
region, the anterior spinal artery receives
contributions from the subclavian arteries. By
the time the blood reaches the T4 segment it
becomes tenuous. Although, the T4 to T9 area of the spinal cord receives blood from the feeder vessels, it is relatively small.
13
Q
- The most common location of the dorsal root ganglion is
(A) medial to the pedicle within the lateral
recess
(B) inferolateral to the pedicle
(C) lateral to the superior articular facet of
the corresponding vertebra
(D) directly below the pedicle
(E) medial to the superior articular facet of
the corresponding vertebra
A
- (D) In approximately 90% of cases the DRG
lies in the middle zone of the intervertebral
foramen, directly below the pedicle. In approximately, 8% of cases it is inferolateral and in 2% of cases it is medial to the pedicle. The center of the DRG lies over the lateral portion of the intervertebral disc in some cases. Its size increases from L1 to S1 and then progressively decreases till S4. The DRG at S1 is 6 mm in width. The DRG contains multiple sensory cell bodies. It is the site for production of neuropeptides: substance P, enkephalin, VIP (vasoactive intestinal peptides), and other neuropeptides.
The DRG is a primary source of pain when
it undergoes mechanical deformity as by an
osteophyte, HNP, or stenosis. It also produces
pain when it undergoes an inflammatory process either by infection or chemical irritation from a herniated nucleus pulposus, release of local neuropeptides or local vascular compromise.
14
Q
14. Absolute central lumbar spinal stenosis is defined as (A) less than 8 mm diameter (B) less than 10 mm diameter (C) less than 12 mm diameter (D) pain at rest (E) pain with ambulation
A
- (B) The spinal canal is nearly round in shape; it is 12 mm or more in the anteroposterior diameter. Relative stenosis is defined as midline sagittal diameter of < 12 mm. The reserve capacity is reduced and any small disc herniation and mild degenerative changes may cause symptoms. Absolute stenosis is defined as a sagittal diameter < 10 mm
15
Q
15. The principal action of the quadratus lumborum muscle is (A) lateral flexion of the lumbar spine (B) axial rotation of the lumbar spine (C) extension of the lumbar spine D) fixation of the 12th rib during respiration (E) forward flexion of the lumbar spine
A
- (D) The principal action of the quadratus lumborum
(QL) muscle is to fix the 12th rib during
respiration. It is a weak lateral flexor of the
lumbar spine. The QL is a flat rectangular
muscle that arises below from the iliolumbar
ligament and the adjacent iliac crest. The insertion is into the lower border of the 12th rib and the transverse processes of the upper four lumbar vertebrae. Patients with spasm of the QL muscle usually present with low back pain. They have difficulty turning over in bed, increased pain with standing upright. Coughing or sneezing may exacerbate their pain. These patients respond
well to trigger point injections and stretching.
16
Q
- The following structure passes under the inguinal
ligament:
(A) Inferior epigastric artery
(B) Lateral femoral cutaneous nerve
(C) Obturator nerve
(D) Intra-articular nerve of the hip joint
(E) Sciatic nerve
A
- (B) The structures that pass under the inguinal ligament, medial to lateral are: femoral vein, femoral artery, inguinal nerve, femoral nerve, and lateral femoral cutaneous nerve. The following muscles also pass under the inguinal ligament: pectineus, psoas major, iliacus. The inferior epigastric artery passes under the rectus sheath. The obturator nerve passes through the obturator foramen. The sciatic nerve is located posteriorly.
17
Q
17. The structure that passes under the flexor reticulum of the wrist is (A) median nerve (B) radial nerve (C) ulnar nerve (D) anterior interosseous nerve (E) extensor digitorum longus
A
- (A) The flexor reticulum (retinaculum) is
fibrous band which is attached medially to the
pisiform and the hamate bone. It is attached laterally to the scaphoid and trapezium. The area under the flexor reticulum is known as the carpal tunnel, through which pass flexor tendons of the digits and the median nerve. The radial and ulnar nerves do not pass under the reticulum. The extensor digitorum longus
tendon lies on the dorsum of the wrist.
18
Q
18. A boxer complains of pain in his hand after punching a bag. What is the most likely cause? (A) Avulsed ulnar ligament (B) Scaphoid fracture (C) Fracture of distal radius (D) Metacarpal fracture (E) Dislocation of the fifth proximal interphalangeal joint
A
- (D) The boxer’s fracture involves the neck of the metacarpal. This is the most common site for fracture when punching a stationary object. The fracture occurs commonly in the fourth and fifth metacarpal bones. A fracture of the scaphoid bone is usually seen after a fall on the outstretched hand. Fracture of the distal radius is also know as Colles fracture and usually occurs after a fall on the outstretched hand.
