Axial Skeleton and Muscles Flashcards
Cervical vertebrae
Seven. Atlas, axis. 3-7 have a ventral crest and gradually increasing spinous processes.
Thoracic vertebrae
Thirteen. All have prominent spines. The first 10 have tall caudally inclining spines. The 11th is the anticlinal vertebra. The 12th and 13th have spines that incline cranially.
Lumbar vertebrae
Seven. All have prominent but blunt spinous processes. Large transverse processes directed cranially and ventrolaterally.
Sacral vertebrae
Three, fused into a single bone. Body of the first segment is larger than the combined bodies of the next two segments.
Caudal vertebrae
Twenty. Lose distinctive features as they move caudally.
Vertebral body
ventral side of the vertebra. constricted centrally. Dogs: cranial extremity convex, caudal extremity concave.
Vertebral arch
dorsal side of the vertebra. Two pedicles (basal) and two laminae (dorsal)
Nucleus pulposus
Soft center of the intervertebral disc.
Anulus fibrosus
Concentric layers of dense tissue, the outer layer of the intervertebral disc.
Vertebral foramen
Main canal formed by the vertebral body and vertebral arch.
Vertebral canal
All vertebral foramina join together to form this.
Cranial vertebral notches
shallow notches formed by the vertebral arch pedicles.
Caudal vertebral notches
Deeper notches than the cranial, formed by the vertebral arch pedicles.
Intervertebral foramina
Spaces that the vertebral notches form with the bodies of adjacent vertebrae, along with the intervening fibrocartilage. Spinal nerves and blood vessels pass through these points.
Spinous process
dorsally located vertebral
Transverse process
lateral vertebral processes from the region where the arch joins the vertebral body.
Articular processes
Cranial and caudal on each vertebra. At the junction of the pedicle and the lamina on the vertebral arch. Cranial articulating surfaces point medially or dorsally, caudal surfaces are ventrally or laterally.
Atlas
1st cervical vertebra. Articulates with the skull cranially. Lacks a spinous process and has a reduced vertebral body.
Wings of the Atlas
Origin of the omotransversarius. Thick shelflike transverse processes of the atlas, which have the transverse foramina running obliquely dorsal/ventral.
Cranial articular fovae of the atlas
On the atlas, fovae that articulate with the occipital condyles of the skull to form the atlanto-occipital joint.
Atlanto-occipital joint
Between the atlas and the occipital condyles of the skull. Main movement is flexion and extension.
Caudal articular fovae of the atlas
shallow glenoid cavities that articulate with the axis.
Atlantoaxial joint
Rotatory movement occurs between the atlas and the axis.
Fovea dentis
Concave part of the dorsal surface of the vertebral body on which the dens of the axis rests.
Transverse foramina of the atlas
Run obliquely through the wings of the atlas. Contain the vertebral artery and vein.
Lateral vertebral foramina of the atlas
Foramina on the vertebral arch of the atlas. Contains the first cervical nerve.
Axis
2nd cervical vertebra. Elongated with large ridgelike spinous process.
Dens of the axis
Cranial peglike prominence that sits in the vertebral foramen of the atlas.
Cranial articular surface of the axis
Contiguous with the dens. Articulates with the caudal articular surface of the atlas to form the atlantoaxial joint around which rotary action of the skull takes place.
Specialization of the 6th cervical vertebra
Tallest spinous process of cervical region
Expanded ventral lamina of the transverse process.
Cranial and caudal articular processes of the cervical vertebrae
Face dorsally and cranially in articulation.
Ventral crest (vertebrae)
on cervical vertebrae 3-7
Cranial and caudal costal fovea
Thoracic vertebrae. Articulations for the head of ribs 1-10.
Anticlinial vertebrae
Thoracic vertebra #11. All spines cranial point caudally while all spines caudal point cranially. This is the tipping point vertebrae.
Articular processes of the thoracic vertebrae
Mostly dorsal/ventral on 1-10. 10-13 lateral/medial.
Caudal articular processes are usually…
Ventral or lateral faces.
Cranial articular processes are usually…
Dorsal or medial faces.
Accessory process
First seen on thoracic vertebrae, lacking on cervical. Caudal projection of the pedicle. Lays ventral to the caudal articular process.
Mamillary process
On thoracic vertebrae. Knoblike dorsal projection of the transverse process (2-10) or knoblike dorsal projection of the cranial articular processes (11-caudal vertebrae). Connect to epaxial muscles of the transversospinalis system.
Articular processes of the lumbar vertebrae
Medial and lateral (on a sagittal plane).
Medial sacral crest
Represents the fusion of the three spinous processes of the fused sacral vertebrae.
Dorsal sacral foramina
2 pairs on dorsal surface of the sacrum. Transmit the dorsal branches of the first two sacral spinal nerves.
Pelvic sacral foramina
2 pairs on the ventral surface of the sacrum. Transmit the ventral braces of the first two sacral spinal nerves.
Auricular face of the sacrum
Articulates with the ilium
Base of the sacrum
Thick cranial portion of the sacrum
Promontory
Ventral transverse ridge of the sacrum.
Costal cartilages
Paired with each rib. Connect to the sternum mainly or help form the costal arch on ribs 10-12.
Rib head
Articulates with the costal fovea of two contiguous ribs on 1-10. 11-13 just articulate with the cranial fovea.
Rib tubercle
Articulates with the costal fovea of the transverse process (of the vertebrae with the same number).
Neck of the rib
Between the head and the tubercle of the rib.
Sternebrae
Eight unpaired segments on the ventral midline.
Intersternebral cartilages
Join consecutive sternebrae.
Manubrium
First sternebrae, has a cranial clublike enlargement
Xiphoid process
Last sternebrae, flattened dorsoventrally.
Axial muscles
Muscles of the trunk and neck
Hypaxial muscles
Manly flexors of the vertebral column.
Epaxial muscles
Mainly extensors of the vertebral column.
Longus capitus
On the lateral surface of the cervical vertebrae. Attachments: transverse processes of the cervical vertebrae and basiooccipital bone.
Longus colli
Many overlapping fascicles, ventral to the longus capitus. Attachments: transverse processes of the cervical vertebrae and adjacent fascicle.
Scalenus
Attachments: first few ribs and transverse processes of the cervical vertebrae.
Action: Inspiration by drawing the ribs forward.
Serratus dorsalis cranialis
O: Aponeurosis deep to the rhomboideus
Median raphe of the neck
I: Craniolateral surfaces of the ribs
A: Lifts the ribs for inspiration
Serratus dorsalis caudalis
O: Aponeurosis from the thoracolumbar fascia
I: caudal borders of the last three ribs
A: Draws last three ribs caudally in expiration.
External intercostal muscles
Fibers run caudoventrally.
Attachments: caudal border of one rib to cranial border of the caudal rib.
Action: Draw the ribs together. Inspiratory or expiratory based on rib position.
Internal intercostal muscles
Fibers run cranioventrally. Pleura attaches to this muscle in the thoracic cavity.
Attachments: cranial border of one rib to the caudal border of the cranial rib.
Action: Draw the ribs together. Inspiratory or expiratory based on rib position.
All four abdominal muscles
external abdominal oblique, internal abdominal oblique, rectus abdominis, transversus abdominis.
External abdominal oblique
Fibers run caudoventrally.
O: costal part from last ribs
lumbar part from thoracolumbar fascia and rib 7 or 8.
I: wide aponeurosis over linea alba and the prepubic tendon.
Superficial inguinal ring
Separation in two parts of the aponeurosis of the external abdominal oblique where vaginal tunic/process and spermatic cord/cremaster muscle in males.
Inguinal canal
Ends in the superficial inguinal ring. Bordered by all four abdominal muscles.
Vaginal tunic/process
Tunic in males, process in females. Process is fatty tissue that will envelop the ligament of the uterus. Tunic is fatty tissue that will enclose the spermatic cord and cremaster muscle.
Inguinal ligament
Caudal border of the aponeurosis of the external abdominal oblique, terminating on the prepubic tendon/iliopubic eminence. Between the superficial inguinal ring and the vascular lacuna.
Vascular lacuna
The base of the femoral triangle under the vessels.
Internal abdominal oblique
Fibers run cranioventrally.
O: Superficial leaf of the thoracolumbar fascia
Tuber coxae and inguinal ligament
I: Wide aponeurosis on the costal arch, linea alba, and prepubic tendon.
Cremaster muscle
Formed from fibers of the caudal border of the internal abdominal oblique. Raises and lowers the testes.
Transversus abdominis
Fibers run transversely
O: Medial surface of last 4-5 ribs
Transverse processes of lumbar vertebrae through thoracolumbar fascia
I: aponeurosis at linea alba
Forms the internal sheath of the rectus abdominis
Rectus abdominus
Fibers run craniocaudally with distinct transverse tendinous intersections
O: Pecten of the pubis as the prepubic tendon
I: Sternum
Deep inguinal ring
On the inside of the abdominal wall in the inguinal canal.
Spermatic cord
Passes through the inguinal canal, carries sperm from testes to penis.
Iliocostalis system
Most ventral of the three epaxial systems
Longissimus system
Middle of the three epaxial systems
Transversospinalis system
Most dorsal of the three epaxial systems
iliocostalis lumborum
O: wing of the ilium
I: transverse processes of lumbar vertebrae
Covered by the thoracolumbar fascia
Iliocostalis thoracis
O: 12th rib
I: transverse process of the seventh cervical vertebra.
longissiumus thoracis et lumborum
O: Crest and medial surface of the wing of the ilium
I: Supraspinous ligament and spines of lumbar and thoracic vertebrae
longissiumus cervicis
Ribs to the transverse processes of the cervical vertebrae
longissiumus capitis
First three thoracic vertebrae to the mastoid part of the mastoid part of the temporal bone.
splenius
Third thoracic vertebra to the skull (nuchal crest and mastoid process)
semispinalis capitus
thoracic vertebrae to the head. Two parts, the biventer cervicus ( dorsal with tendinous intersections) and the complexus (ventral).
nuchal ligament
From the tip of the spinous process of the first thoracic vertebra to broad caudal end of the axis. Between the medial surfaces of the semispinalis captitus muscles.
supraspinous ligament
continues the nuchal ligament caudally, running over the top of the spinous processes and joining them together. From first thoracic vertebra to 3rd caudal vertebra.
Transverse ligament of the atlas
Attaches on the dorsal side of the vertebral body on either side of the dens and holds it to the fovea dentis
Apical ligament
Cranial end of the dens to the basioccipital bone. Thin v shape medial to the alar ligaments
Alar ligament
Cranial end of the dens to the basioccipital bone in a wide v (lateral to the apical ligaments).
Dorsal atlantoaxial ligament
Attaches the spine of the atlas to the vertebral arch of the atlas.
Intervertebral discs
Between vertebral bodies. Outer ring is thick annulus fibrosis and inner ring is gelatinous nucleus pulposus.
Ventral longitudinal ligament
Runs along the ventral surfaces of the vertebral bodies
Sacrum to the axis
Dorsal longitudinal ligament
Dorsal part of the vertebral spine running from sacrum to axis
Yellow ligaments
Lateral to the midline, extending between vertebral arches. Cover the epidural interarcuate space between the articular processes.
Interspinous ligaments
Connect adjacent spinous processes.
Intercapital ligament
Connects left and right rib heads. Extends across the dorsal side of the annulus fibrosus ventral to the dorsal longitudinal ligament.
Holds ribs in place and provides containment for intervertebral discs.
