Vertebral Column and Muscles of the Back

The only plane that intersects 2 halves and creates equal planes is ___

the medial plane

Any plane that is slightly off the medial plane (off to the side) is the ___

sagittal plane

When looking at CTs or MRIs, this is the ___

transverse plane

The sole of the foot can also be referred to as the ___

plantar surface of the foot

Proximal means ___

Distal means ___

closer to; further away

The knee is ___ to the hip

distal

The hip is more ___ to the belly button than the knee

more proximal

Posterior means ___

Anterior means ___

dorsal; ventral

Layers of skin:

superficial (top)

intermediate

deep (inner)

Top of hand is called ___

Bottom on hand is called ___

dorsum; palm (sole for foot)

What is it called when you straighten your arm?

extension

-bending arm up is flexion

Flexion is ___

Extension is ___

moving the upper and lower limb forward; opposite, moving upper/lower limbs backwards

Curling body forward (like a C) is called ___

Flexion

-flexion is bending back leg (knee joint)

Moving something away from the midline is ___

Abduction

Moving something toward the midline is ___

Adduction

Moving your foot towards the dorsal side of foot is ____

dorsiflexion

-moving down (planting on ground) is plantarflexion

Supination is ___

holding a bowl of soup (in palm of hand)

-Pronation is flipping wrist so palm is down

"Normal" range of motion is evident in ___

young healthy individuals and reduced by >50% with increasing age

-influenced by intervertebral discs, structure of the zygoapophysial joints, ligaments associated with the vertebral column, attachment to other bony structures, and associated muscle and adipose tissue

Regions of Vertebrae:

-Cervical (7)

-Thoracic (12)

-Lumbar (5)

-Sacrum (fused 5)

-Coccyx (3-5)

The strongest vertebrae are in the ___ region

Lumbar region

-weight bearing increases as you go down spine

The lumbar curvature is more denoted in ___

females

-exaggerated during pregnancy (excessive lordosis)

The sacral curvature is diff in females as it is less acute which ___

limits protrusion of the coccyx into the birth canal

The concavity of the thoracic and sacral region are ___

anterior (kyphosis)

-while being posteriorly placed in the cervical lumbar region (lordosis)

When do the primary curvatures of the back exist?

during fetal development

-thoracic and sacral curvatures maintained throughout life

When do secondary curvatures of the back develop?

later on and are dependent on growth and development of intervertebral disc

When does the cervical curvature begin to develop?

when infants begin to hold up their heads

When does the lumbar curvature develop?

with initiation of walking

What does a vertebra consist of?

1. a body (more dense anteriorly)

2. an arch (consist of lamina and pedicle)

3. 7 processes (spinous, 2 transverse, and 4 articular (2 superior/2inferior))

The vertebral arch and posterior aspect of body created the boundaries of the ___

vertebral foramen

-with all of the vertebral foramina stacked --> vertebral canal

The inferior vertebral notch of the superior vertebra in relationship to the superior vertebral notch of the inferior vertebra creates the ___

intervertebral foramen

-allows for passage of spinal nerves

Specific Characteristics of Cervical Vertebrae:

1. body is the smallest of all of the regions of the vertebral canal

2. vertebral foramen is large and has triangular shape

3. The transverse processes of C1-C6 have foramen (allow for ascension of vertebral arteries)

4. spinous processes of C3-C5(6) are bifid in nature

5. C3-C7 are considered “typical”

6. C1-C2 are "atypical"

7. C1: Atlas, C2: Axis

8. flexion is greatest in this region

Characteristics of C1 Atlas:

1. Ring-like

2. No spinous process or body, but rather has an anterior and posterior arch

3. The superior articular facets, in association with the occipital condyles, create the atlanto-occipital joints

4. The inferior articular facets, in association with C2, create the atlanto-axial joints.

Characteristics of C2 Axis:

1. considered the strongest cervical vertebra

2. the dens (odontoid process) is believed to be the body of C1

The atlas pivots around the ___

dens with lateral/medial rotation

-dens articulates with anterior arch of C1

Characteristics of Thoracic Vertebrae:

1. Body is heart shaped and has costal facets where the ribs articulate

2. The vertebral foramina is smaller

3. The spinous processes are long with a posteroinferior slope (which limits flexion). The tip reaches the vertebral body inferior to it

4. T1-T10 have transverse costal facets which articulate with a portion of the ribs

5. The transverse processes are long

Characteristics of Lumbar Vertebra:

1. Body is massive and dense

2. Spinous processes are blunted

3. The vertebral foramina are the largest in this region and triangular in shape

4. The transverse processes are long and slender

Characteristics of Sacral Vertebrae:

1. provide stability for the pelvis, with transmission of body weight via the sacroiliac joints

2. The base of the sacrum (S1) articulates with L5. It’s anterior edge projects and is referred to as the promontory

3. The superior-lateral edge of the sacrum is called the ala (Latin for wing)

S1-S3 have both ___ and ____ for the sacral vertebrae

lamina and pedicles

-absence of these structures creates a hiatus on posterior aspect of the sacrum

-Coccyx: remanent of the tail-life embryonic caudal eminence

Ligaments and Intervertebral Disc:

1. anterior longitudinal ligament: fibrous band that covers and connects the anterior surface of the vertebral bodies and the associated IV disc

2. posterior longitudinal ligament: not a wide or strong as the anterior. Runs in the vertebral canal, covering the posterior aspect of the vertebral bodies (from C2-sacrum)

3. Ligament flavum: yellow, elastic ligament covers the lamina of the vertebral canal

4. intervertebral disc: Anulus Fibrosus (outer portion) and Nucleus pulposus (central core: contains water, elastin and proteoglycans)

What is the function of the anterior longitudinal ligament?

traverses from the pelvic surface of the sacrum to the anterior tubercle of C1 (including the occipital bone)

-limits the extension of the vertebral column

What is the function of the Posterior longitudinal ligament?

important for the prevention of hyperflexion of the vertebral column and posterior herniation of IV disc

What is the function of the ligamentum flavum?

important for protection of the IV discs during sudden flexion of the column

-also preserves the curvatures of the column and assist with straightening the back after flexion

Arterial Supply of Vertebral Column:

•Periosteal branches

•Equatorial branches

•Spinal branches:

–Anterior vertebral canal br

–Posterior vertebral canal br

Periosteal and Equatorial branches:

arises from cervical and segmental arteries

Spinal Branches:

arise from vertebral, ascending cervical [neck], posterior intercostal [thorax], subcostal, lumbar [abdomen], iliolumbar and lat/med sacral a [pelvis].

Venous Drainage of Vertebral Column:

•Spinal v.: Internal vertebral (epidural) venous plexus (anterior/posterior) AND External vertebral venous plexus (anterior/posterior)

•Basivertebral v.

•Intervertebral v.

Basivertebral vein:

drain into internal venous plexi --> external venous plexi

Intervertebral vein:

receives blood from the spinal cord and the vertebral plexi, exits through the intervertebral foramina and drains into the vertebral/segmental v. of the neck and trunk

What is the nuchal groove?

site of nuchal ligament in the back

In the trapezius muscle:

D: descending

T: transverse

A: ascending

What are extrinsic back muscles responsible for?

limb movement and control

-also respiratory movement

What are intrinsic back muscles responsible for?

act on spinal column to produce movement

-responsible for posture

Superficial Extrinsic Division of back muscle:

Functions primarily to produce and control limb movement

-innervated by ventral rami (1 exception is trapezius CN XI)

Muscles of the Superficial Extrinsic division:

•Trapezius m.

•Latissimus dorsi m.

•Levator scapulae m.

•Rhomboid m. (major/minor)

Intermediate Extrinsic Division of back muscles:

Functions as superficial respiratory muscles

-innervated by intercostal nerves (ventral rami)

Muscles of the Intermediate Extrinsic division:

-Serratus posterior superior m.

-Serratus posterior inferior m.

Intrinsic (deep) Back muscles:

maintain posture and control the movements of the vertebral column

-innervated by dorsal rami of spinal nerves

Muscles of Intrinsic (deep) back muscles:

Superficial: Splenius m.

–Capitis

–Cervicis

Intermediate: erector spinae m.

Deep: Transversospinales muscle group

–Semispinalis

–Multifidus

–Rotatores

What is the collective name for a group of 3 muscles which lie in the space between the spinous processes of the vertebrae and the costal angles?

Erector spinae

The Transversospinales muscle group is composed of 3 specific muscles:

Semispinalis, Multifidus, Rotatores

-reside in the space between the spinous and transverse processes of the vertebral column

Trapezius Muscle:

innervation: CN XI

function: Elevation, depression, and retraction of the scapula

blood supply: transverse cervical artery

Where is the insertion of trapezius muscle?

lateral 1/3 of clavicle, acromion, and spine of scapula

Lattisimus Dorsi muscle:

innervation: throacodorsal nerve

Fx: Adduction of upper extremity, internal rotation, extend upper extremity

blood supply: thoracodorsal artery

Where is the insertion of the Lattisimus Dorsi?

intertuberular groove of humerus

Levator scapulae:

Innervation: Dorsal scapular n.

Fx: elevates scapula

Blood supply: dorsal scapular a

Rhomboids:

Innervation: Dorsal scapular n.

Fx: retract and rotate scapula; fix scapula to thoracic wall

Blood supply: Dorsal scapular a.

Rhomboid minor:

-Medial attachment: nuchal ligament and spinous processes of C7-T1

-Lateral attachment: medial end of scapular spine

Rhomboid major:

-Medial attachment: spinous processes of T2-T5

-Lateral attachment: medial end border of scapula from spine to inferior angle

Trapezius (sup and inf fibers) cause __ rotation of scapula

superior rotation

-rotation elevating glenoid cavity

Rhomboids cause ___ rotation of the scapula

inferior rotation

-rotation depressing glenoid cavity

Serratus Posterior Superior muscles:

-Innervation: 2-5th intercostal n.

-Fx: Elevate ribs

Serratus Posterior Inferior muscles:

Innervation: 9-11th intercostal n and subcostal n (T12)

Fx: Depresses ribs

Splenius muscles:

innervation: posterior rami of spinal nerves

Fx: extend head and neck (together) and laterally flex neck and rotate head (alone)

Blood supply: muscular branches of aorta and branches off posterior intercostal a

Erector Spinae:

Innervation: posterior rami of spinal n

Fx: laterally flex column (unilaterally) and controls flexion of spine by lengthening its fibers (bilaterally)

Blood supply: branches off aorta

What are the ILS muscles?

Iliocostalis, Longissimus, and Spinalis

Back Sprain:

injury to ligaments

-without dislocation or fracture

-from excessive extension/rotation

Back Strain:

stretching or tearing of muscle

-usually in lumbar region and involving the erector spinae m.

-MOST COMMON cause of lower back pain

-unbalanced weight on vertebral column pulls muscles (spasms occur)

What do you have to think about with lower back pain (LBP)?

bulging discs (herniation of nucleus pulposus)

-can compress spinal cord, spinal nerves, or nerve roots of cauda equina

What is a sciatica?

pain in the lower back and hip from compression of the L5 or S1 portion of the sciatic nerve

-can occur from herniation or the development of osteophytes (bony spurs) in the vertebral foramen

Spondylolysis:

-fracture of the vertebral lamina

-occurs at L5, thought to develop because of embryonic failure

-contributes to the development of spondylolisthesis

What is the most common embryonic anomaly of the vertebral column?

spina bifida

-failure of the laminae to develop and fuse

-L5 and/or S1

-24% of people

Lumbar puncture (spinal tap):

Aseptic procedure

-Between L3 and L4 -or- L4 and L5

Other nerve blocks:

-direct effect of the spinal nerves of the cauda equina as they exit the dural sac

-can also be done in the sacral canal or through the posterior sacral foramina