Back Muscles Flashcards
-Muscle that runs from the transverse process of upper cervical vertebra to the medial border of the scapula
-Elevates the scapula
-Dorsal Scapular Nerve (C5)
Levator Scapulae Muscle
-Spinal Accessory Nerve (CN XI)
-most superficial muscle, overlays levator scapulae
-Upper, middle, and lower portions
-Upper: Shoulder elevation/extension of the head & neck
-Middle: Shoulder retraction
-Lower: Scapular depression and upward rotation
Trapezius Muscle
-Thoracodorsal Nerve
-originates from thoracolumbar fascia and iliac crest and inserts on the Bicipital (Intertubercular) Groove of the Humerus
-IR, Adducts, and Extends the GH Joint (same as Teres Major)
Latissimus Dorsi Muscle
-Dorsal Scapular Nerve (C5)
-Deep to trapezius (same level as Levator Scapulae)
-Major and Minor (sometimes can’t differentiate between them)
-Originates on the spinous processes of the 2nd-5th thoracic vertebra and inserts on the medial border of the scapula
-Retract and rotate the scapula medially and upward
Rhomboid Muscles
-Extend the back (stand up straight), allow vertebra to rotate on themselves (look from side to side), and stabilize vertebrae (don’t let them slide around)
Function of Intermediate Back Muscles
What is the innervation for the intermediate back muscles?
Motor branches of the dorsal primary rami.
-Segmental: not just a single nerve that goes out. Go segment by segment all the way down.
Has medial and lateral branches. Curves around off of spinal nerve and goes in dorsal direction. Divides as it enters the back muscles:
-Medial branch: goes to skin. chiefly sensory.
-Lateral: stays within muscles, so motor branch
Dorsal Primary Rami
Splits off of spinal nerve and goes to innervate plexi
Ventral Primary Rami
Cluster of intermediate back muscles
-Function: erects the spine. Helps us stand up straight
-Iliocostalis Group
-Longissimus Group
-Spinalis Group
Erector Spinae
Most Lateral Erector Spinae Group.
-Iliocostalis Cervicis: attaches to cervical spine
-Iliocostalis Thoracis: attaches to vertebra of thoracic spine
-Iliocostalis Lumborum: Attaches to lumbar vertebra
Iliocostalis Group
Middle Erector Spinae Group
-Longissimus Capitis
-Longissimus Thoracis
-Longissimus Cervicis
Longissimus Group
Most medial erector spinae group; right up against the spinous processes.
-Spinalis Capitis
-Spinalis Thoracis
-Spinalis Cervicis
Spinalis Group
Thin muscles that help to stabilize the spine and rib cage
-Superior: Contract to elevate ribs to expand chest to inhale. Attach to ribs from vertebral column.
-Inferior: reverse function. Contract to pull ribs down to forcefully exhale. Run from lumbar vertebra to lower rib cage
Serratus Posterior Superior & Inferior Muscles
Deepest group of back muscles.
-Run from transverse processes out to spinous processes
Superficial to Deep:
-Semispinalis, Multifidus, and Rotatores
Transversospinalis Group
Deep Group of muscles. Most superficial of the deep group.
-Mostly tendon
-Cross about 4-6 vertebral segments (Thoracis, Cervicis, and Capitis)
-Run diagonally; originate on transverse processes and insert in a diagonal direction on the spinous process of a vertebra 4-6 segments up.
Semispinalis Group
Deep muscle. Short but powerful.
-Cross 2-4 vertebral segments
-Best muscles for extension
-Run from transverse process to spinous process
-Sacralis, Lumborum, Thoracis, and Cervicis regions
Multifidus Group
Deepest group of deep muscles.
-Tiny muscles, cross 1-2 vertebral segments
-If 1: Brevis. If 2: Longus
-Short muscles lying between the vertebrae
-Run from transverse process to ribs.
-Sacralis, Lumborum, Thoracis, Cervicis
Rotatores Group
A minor deep back muscle group; located between the transverse processes of vertebrae.
-Gives strength to the spinal column and holds it together as one unit.
-Has a lumbar and cervical group
Intertransversarii Group
A minor deep back muscle that runs between the spinous processes of vertebrae. Assists with spine stability.
-Has a lumbar and cervical group
Interspinales Group
Muscles that originate from transverse processes of thoracic vertebra and insert diagonally on the rib directly below or two ribs below it.
-Stabilization of the vertebral column against the ribs
-Can switch origin and insertion to lift the ribs up to inhale deeply
Levatores Costarum Muscles
A “V” shaped muscle that starts on the cervical vertebra and attaches to ligamentum nuchae and attaches to the back of the head.
-Inserts on the Mastoid Process
-Lies just deep to the Upper Trapezius m.
Splenius Capitis m.
A muscle distal to the splenius capitis m.,
-Runs parallel to splenius capitis m.
-Attaches medially to the ligamentum nuchae
Splenius Cervicis m.
Medial and Deep to Splenius Capitis.
-Fibers run straight up and down
-Attaches to the back of the head along the nuchal line
-Innervated by segmental nerves
Semispinalis Capitis m.
Deep to the Semispinalis Capitis m.
-Forms an upside down “V” with the R and L muscles
-Vertex points upward and inserts on the Spinous Process of C2.
-Innervated by segmental nerves
Semispinalis Cervicis m.
What are the muscles of the Occipital Triangle?
Rectus Capitis Posterior Major & Minor m.
Superior/Inferior Obliquus Capitis m.
-Function is to stabilize skull on spinal column
What are the contents of the Suboccipital Triangle?
-Vertebral Artery (running horizontally)
-Suboccipital Nerve (DPR of C1) (innervates muscles of triangle)
-Posterior Bony Arch of C1 Vertebra
-Greater Occipital Nerve
Nerve that comes off of C2 and emerges just underneath the lamina and exits out of the inferior aspect of the Suboccipital Triangle.
-Turns and goes across triangle, comes up, and grabs a little bit of Ligamentum Nuchae before spreading branches for sensory innervation to the back of the head
-No motor; just sensory
-Remember: V1 supplies sensation to forehead and all the way back to the crown. Sensation past the crown is this nerve.
Greater Occipital Nerve (C2)
