Items tagged “spine”

The ligamentum nuchae or nuchal ligament is a large median ligament composed of tendons and fascia located between the posterior muscles of the neck. Gross anatomy The ligament nuchae covers the spines of C1 to C6 vertebrae. It is a superior and posterior extension of the supraspinous ligamen...

Facet joint capsules are the fibrous capsule that surround the vertebral facet or zygapophyseal joints. They are particularly thin and loose, attached to the margins of articular facets on adjoining articular processes. The capsules merge medially with the ligamentum flavum.  In the cervical re...

The suboccipital muscle group contains four paired muscles, three of which pairs belong to the suboccipital triangle. These muscles all lie below the occipital bone and are responsible for postural support of the head, as well as extension, lateral flexion and rotation. As these muscles are smal...

The splenius capitis is a strap-like muscles that, along with the splenius cervicis, comprise the superficial layer of intrinsic back muscles. Gross anatomy Attachments origin: ligamentum nuchae, and the tips of the spinous processes and associated supraspinous ligaments of C7 and the upper t...

The splenius cervicis is part of the superficial layer of the intrinsic back muscles. It is one of the two muscles in this group, the other being the splenius capitis. Summary origin: spinous processes of T3-T6 insertion: transverse processes of C1-C3 innervation: dorsal rami of the lower ce...

The erector spinae group is the intermediate layer of the intrinsic muscles of the back. This group is made of three subgroups, with the group divisions occurring by location. spinalis subgroup is the most medial longissimus subgroup is between spinalis and iliocostalis iliocostalis subgroup ...

The transversospinalis muscle group is the deep layer of the intrinsic back muscles. These muscles lie between the transverse and spinous processes and are grouped by length of the fascicles, as well as region covered. The groups are rotatores, multifidus, and semispinalis. Gross anatomy Rotat...

The anterior corticospinal tract is formed at the level of the of the medullary pyramids, where the majority (90%) of descending corticospinal tract fibers decussate to form the lateral corticospinal tract. The majority of the remaining non-decussating 10% of fibers form the much smaller anterio...

The lateral corticospinal tract is formed at the level of the of the medullary pyramids when the majority (90%) of descending corticospinal tract fibers decussate. The remaining 10% do not decussate and form the much smaller anterior corticospinal tract. A few non-decussated fibers may enter the...

The spinocerebellar tracts are afferent neurons that convey proprioceptive data from the spinal cord to the cerebellum. There are anterior and posterior spinocerebellar tracts, also eponymously named the Gowers tract and Flechsig tract respectively. Both the anterior and posterior spinocerebella...

The corticorubral tract contains neurons that connect the primary motor and sensory areas to the red nucleus. The rubrospinal tract then descends through the spinal cord.  The tract is thought to excite flexor muscles and inhibit extensor muscles. Gross anatomy Central connections The corti...

The rubrospinal tract contains neurons that carry signals from the corticorubral tract. The tract is thought to excite flexor muscles and inhibit extensor muscles. Gross anatomy Central connections The magnocellular portion of the red nucleus gives rise to the rubrospinal tract. It decussates...

The lateral spinothalamic tract, also known as the lateral spinothalamic fasciculus, is an ascending pathway located anterolaterally within the peripheral white matter of the spinal cord. It is primarily responsible for transmitting pain and temperature as well as coarse touch.  The anterior sp...

The anterior spinothalamic tract, also known as the ventral spinothalamic fasciculus, is an ascending pathway located anteriorly within the spinal cord, primarily responsible for transmitting coarse touch and pressure.  The lateral spinothalamic tract (discussed separately), in contrast, primar...