MSA Exam 1 Study Guide: Skull, Spine, Trunk & Thoracic Cage

Vocabulary flashcards defining muscle attachments, actions, innervations, ligaments, joints, motion planes, and bony landmarks from the Skull, Spine, Trunk & Thoracic Cage study guide.

Iliocostalis

The most lateral column of the erector spinae group; originates from the posterior iliac crest, sacrum, sacroiliac ligaments, and lumbar spinous processes, inserting on rib angles and cervical transverse processes.

Longissimus

The intermediate (middle) column of the erector spinae group; originates from the common erector spinae tendon and inserts on ribs, thoracic/cervical transverse processes, and mastoid process.

Spinalis

The most medial column of the erector spinae group; originates from lower thoracic and lumbar spinous processes and inserts on upper thoracic and cervical spinous processes.

Anterior Scalene

A neck muscle originating from anterior tubercles of transverse processes C3–C6 and inserting on the 1st rib; elevates rib 1, performs ipsilateral lateral flexion, and assists neck flexion.

Middle Scalene

A neck muscle originating from transverse processes C2–C7 and inserting on the 1st rib; elevates rib 1 and performs ipsilateral lateral flexion.

Posterior Scalene

A neck muscle originating from transverse processes C4–C6 and inserting on the 2nd rib; elevates rib 2 and performs ipsilateral lateral flexion.

Sternocleidomastoid (SCM)

Muscle originating from manubrium and medial clavicle and inserting on mastoid process and lateral superior nuchal line; bilateral action flexes cervical spine, while unilateral action causes ipsilateral lateral flexion and contralateral rotation.

Upper Trapezius

Superior portion of trapezius muscle responsible primarily for scapular elevation and upward rotation.

Middle Trapezius

Middle portion of trapezius muscle responsible primarily for scapular retraction.

Lower Trapezius

Inferior portion of trapezius muscle responsible primarily for scapular depression and upward rotation.

Rhomboid Minor

Muscle originating from nuchal ligament and spinous processes C7–T1, inserting at medial end/root of scapular spine to retract, downwardly rotate, and stabilize the scapula.

Rhomboid Major

Muscle originating from spinous processes T2–T5, inserting at medial border of scapula below scapular spine to retract and downwardly rotate the scapula.

Levator Scapulae

Muscle originating from transverse processes C1–C4 and inserting on superior medial border/superior angle of scapula to elevate and downwardly rotate the scapula.

Sagittal Plane

Anatomical plane dividing body into left and right halves; major movements are flexion and extension about a mediolateral axis.

Frontal Plane

Anatomical plane dividing body into front and back halves; major movement is lateral flexion about an anteroposterior axis.

Transverse Plane

Anatomical plane dividing body into top and bottom halves; major movement is rotation about a vertical axis.

Ligamentum Flavum

Yellow elastic ligament connecting lamina to lamina of adjacent vertebrae that limits excessive spinal flexion and aids return toward extension.

Anterior Longitudinal Ligament (ALL)

Ligament along anterior surface of vertebral bodies that limits excessive extension (hyperextension).

Posterior Longitudinal Ligament (PLL)

Ligament along posterior surface of vertebral bodies inside vertebral canal that limits excessive flexion.

Supraspinous Ligament

Ligament connecting tips of adjacent spinous processes from C7 to sacrum, limiting spinal flexion.

Annulus Fibrosus

Strong fibrocartilaginous outer fibrous ring of an intervertebral disc.

Nucleus Pulposus

Gel-like center of an intervertebral disc that helps distribute compressive forces.

Vertebral Artery

Vessel traveling through transverse foramina of cervical vertebrae (entering at C6) and entering skull via foramen magnum to supply posterior brain.

Atlas (C1)

First cervical vertebra; has no body or normal spinous process and articulates with occipital condyles allowing 'YES' motion (flexion/extension).

Axis (C2)

Second cervical vertebra; features dens (odontoid process) around which C1 rotates allowing 'NO' motion (rotation).

True Ribs

Ribs 1–7; attach directly to sternum through their own costal cartilage.

False Ribs

Ribs 8–10; do not attach directly to sternum, but join cartilage immediately above.

Floating Ribs

Ribs 11–12; have no anterior attachment to sternum.

Sternoclavicular (SC) Joint

Articulation between medial clavicle and manubrium; the only direct bony articulation connecting upper extremity to axial skeleton.

Atlanto-occipital (AO) Joint

Joint between occipital condyles and C1 atlas, permitting primarily flexion and extension ('YES' motion).

Atlantoaxial (AA) Joint

Joint between C1 and C2 with dens as pivot, permitting primarily rotation ('NO' motion).

Lordosis

Inward/anteriorly convex spinal curvature, normally found in cervical and lumbar regions.

Kyphosis

Posteriorly convex spinal curvature, normally found in thoracic spine.

Scoliosis

Abnormal lateral curvature of spine, often accompanied by vertebral rotation.

Spondylolisthesis

Condition where one vertebra slips relative to vertebra below it (such as L5 slipping anteriorly over S1).

Tuffier's Line

Imaginary horizontal line drawn between tops of iliac crests passing approximately through L4 or L4–L5.

Vertebra Prominens

Common designation for C7 vertebra due to its prominent spinous process at base of neck.