Cat Skeleton: Anatomy, Bones, and Function

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-09-20

The cat skeleton is a lightweight, highly mobile framework of roughly 230 to 250 bones that supports the body, protects internal organs, stores minerals, and produces blood cells. Its most distinctive features are a flexible spine with more vertebrae than a human has, a compact skull built for a short powerful bite, and limbs engineered for silent stalking, climbing, and landing from height.

This guide walks through the cat skeleton region by region, gives the vertebral formula and dental formulas, and explains how feline bones differ from those of dogs and other mammals.

This article is educational and is not a substitute for veterinary diagnosis or treatment.

The Cat Skeleton at a Glance

Veterinarians describe the skeleton in two divisions. The axial skeleton runs down the midline and includes the skull, vertebral column, ribs, and sternum. The appendicular skeleton includes the limbs and the girdles that attach them to the trunk.

A working bone count for the domestic cat is summarized below. Counts vary slightly between individuals because of sesamoid bones (small bones embedded in tendons) and because the number of tail vertebrae differs from cat to cat.

The exact total depends on how sesamoids are counted. The feline manus alone contains multiple small sesamoid bones associated with the digits, and detailed anatomical work on the paw has described the diameters of the digital sesamoid bones in domestic cats [1].

The Skull

The skull is the most complex part of the cat skeleton. It has two functional halves. The neurocranium is the bony box around the brain. The viscerocranium (facial skeleton) supports the face, jaws, and nasal cavity.

Cranium and Sutures

The cranial vault is formed by the frontal, parietal, occipital, interparietal, and temporal bones, joined by fibrous joints called sutures. In the domestic cat the sagittal crest, a ridge along the top of the skull where jaw muscles attach, is modest. In the Muñoa's pampas cat, a small wild felid, the crest is described as minimally developed, and the mastoid processes are reduced [2]. Domestic cats follow a similar general plan.

The frontal sinuses sit within the frontal bone. In the pampas cat these sinuses are trapezoidal and located at the level of the postorbital process [2]. Sinuses reduce skull weight while maintaining strength.

Facial Skeleton and Jaw

The maxilla carries the upper teeth and forms most of the hard palate. The zygomatic arch is the bony bridge on each side of the skull between the eye socket and the ear region. It provides attachment for the masseter and temporalis muscles, the main closers of the jaw. In the pampas cat the rostral zygomatic arches show slight lateral expansion [2].

The mandible is the lower jaw. Its coronoid process, the upright projection near the jaw joint, is one of the three bony landmarks that reliably distinguish male from female cats. In a morphometric study of 38 dried feline skulls and pelvic bones, the coronoid process of the mandible separated the sexes with 88.2% accuracy [3].

The hyoid apparatus is a chain of small bones in the throat that suspends the larynx and tongue. It is included in skull bone counts because it develops from the same embryonic arch structures.

The Sella Turcica

The sella turcica is a saddle-shaped depression on the ventral surface of the cranium that houses the pituitary gland. Because of this close relationship, its shape and size carry clinical information. Computed tomography measurements of the sella turcica in 33 adult cats found significant sex-based differences in sella diameter, cranial sella height, and sella width, and all skull measurements were larger in male cats [4]. This is a good reminder that normal feline skeletal dimensions are not identical across sexes.

Dental Formula

Cats are carnivores with specialized teeth for shearing meat. The dental formulas are:

• Deciduous (baby) teeth: 2 × (3 incisors, 1 canine, 3 premolars) upper and 2 × (3 incisors, 1 canine, 2 premolars) lower = 26 teeth total.
• Permanent (adult) teeth: 2 × (3 incisors, 1 canine, 3 premolars, 1 molar) upper and 2 × (3 incisors, 1 canine, 2 premolars, 1 molar) lower = 30 teeth total.

The upper jaw has one more premolar per side than the lower jaw, and the lower jaw has one fewer molar per side. The large upper fourth premolar and the lower first molar together form the carnassial pair, the shearing blades used to slice meat.

Tooth number can vary. In the pampas cat, the second upper premolar (P2) was present in most specimens, showing that small premolars are not always lost in felids [2]. Similar minor variations occur in domestic cats.

The Vertebral Column

The vertebral column is where the cat skeleton earns its reputation for flexibility. The feline formula is:

C7, T13, L7, S3, Cd 20 to 23

That means 7 cervical vertebrae, 13 thoracic, 7 lumbar, 3 sacral, and roughly 20 to 23 caudal (tail) vertebrae. The total is 50 to 53 vertebrae, compared with 33 in humans.

Cervical Vertebrae (7)

All mammals have seven cervical vertebrae, and the cat is no exception. The first is the atlas (C1), which supports the skull and allows the head to nod. The second is the axis (C2), which provides the pivot for turning the head side to side. The remaining cervical vertebrae are small and mobile, giving cats their wide head range.

A CT study of the feline vertebral canal in 35 cats found that canal circularity was highest at C3, meaning the spinal canal is roundest there [5]. The canal was least circular at C1, the atlas, where the shape changes to accommodate the spinal cord and the joint with the skull.

Thoracic Vertebrae (13)

Thoracic vertebrae carry ribs. Each has a pair of facets for rib attachment. The cat has 13 thoracic vertebrae and 13 rib pairs, one more thoracic segment than the dog's typical 13 but with a different rib arrangement in some individuals. The anticlinal vertebra, the point where the spinous processes change angle, is usually around T11 in cats.

Canal circularity was highest at T6, and the transition zone at T13 and L1 had the lowest circularity, reflecting the change in spinal curvature between the chest and lower back [5].

Lumbar Vertebrae (7)

Cats have seven lumbar vertebrae, compared with six or seven in dogs depending on breed. Extra lumbar vertebrae add length and flexibility to the lower back, which supports the cat's characteristic arching and twisting motion.

The lumbar region is a common site for spinal disease. An extradural meningioma, a tumor outside the dura mater, has been reported at the L5 to L6 level in a cat, where it mimicked a disc herniation [6]. This shows why the lumbar vertebrae matter clinically, not just structurally.

Sacral Vertebrae (3)

Three sacral vertebrae fuse into a single sacrum that links the spine to the pelvis. The sacrum transfers the weight of the hindquarters to the pelvic limbs. The sacroiliac joint, where the sacrum meets the ilium, is the most commonly injured pelvic structure in feline trauma. In a study of 80 cats with pelvic trauma, sacroiliac luxation was the most common lesion, and 91.2% of cats had multiple pelvic lesions [7].

Caudal Vertebrae (20 to 23)

The tail contains about 20 to 23 caudal vertebrae, though the number varies by individual and by breed. The first few caudal vertebrae retain full vertebral structure. Toward the tip they reduce to simple rods. The tail serves as a counterbalance during running and jumping, and it communicates mood.

Ribs and Sternum

The cat has 13 pairs of ribs, one pair per thoracic vertebra. They divide into three groups:

• True ribs (first 9 pairs): attach directly to the sternum by their own costal cartilage.
• False ribs (pairs 10 to 12): their costal cartilages join the cartilage of the rib above rather than reaching the sternum directly.
• Floating ribs (pair 13): the last pair ends in the abdominal wall muscle without attaching to the sternum.

The sternum is a segmented bone in the floor of the chest. It has a manubrium at the front, a series of sternebrae in the middle, and a xiphoid process at the back. The sternum protects the heart and great vessels.

The thoracic skeleton is a common subject of advanced imaging. A detailed anatomical atlas of the feline thorax and abdomen correlated cross-sectional slices with contrast-enhanced CT and 3D reconstructions, successfully identifying all major bones, muscles, and organs of the region [8]. Contrast enhancement markedly improved visualization of vascular anatomy [8]. This kind of reference work supports both teaching and surgical planning.

The Forelimb

Each forelimb contains about 25 bones. The forelimb attaches to the trunk by muscle rather than a bony joint, which is a key feature of the cat skeleton.

Shoulder Girdle

The scapula is a flat triangular bone on the side of the chest. Cats have a reduced clavicle, a small bony or cartilaginous remnant that does not connect the scapula to the sternum. This free-floating arrangement absorbs shock when the cat lands and allows the shoulders to move independently, which is why cats can squeeze through narrow gaps.

Brachium (Upper Arm)

The humerus is the single bone of the upper arm. Its head fits into the shallow glenoid cavity of the scapula, forming a joint with a wide range of motion. The feline shoulder and brachium muscles have been mapped in detail, including their attachments, innervation, and arterial supply, to establish homologies across felids [9]. That work reported anatomical variants in the domestic cat and noted that cats are used as a representative mammalian model in comparative anatomy [9].

Antebrachium (Forearm)

The forearm has two bones. The radius is the main weight-bearing bone on the cranial side. The ulna lies caudal and forms the point of the elbow, the olecranon. In cats the two bones retain more independence than in dogs, which contributes to forearm rotation during climbing and prey handling.

Manus (Paw)

The paw includes the carpal bones (arranged in two rows), the metacarpals (one per digit), and the phalanges. Cats have five digits on each forepaw, including a dewclaw, and four weight-bearing digits on each hind paw.

The flexor mechanism is elaborate. The flexor digitorum superficialis gives off five extensions to the digits and forms a fibrous sleeve called the manica flexoria on all but the first digit [1]. Each manus contains four lumbrical muscles and five vincula tendinum, which are fibroelastic bands carrying blood vessels to the tendons [1]. The first digit has its own set of small muscles, including an abductor pollicis brevis [1].

Retractile Claws

Cats are digitigrade, meaning they walk on their toes. The claw of each digit is retractile. A dorsal elastic ligament pulls the distal phalanx and claw back into a sheath when the flexor muscles relax. When the cat contracts the deep digital flexor, the claw extends for climbing or catching prey. Dogs cannot retract their claws in the same way.

The Hindlimb

Each hindlimb contains about 24 bones. The hindlimb connects to the spine through a true bony joint at the sacroiliac articulation, unlike the forelimb.

Pelvis

The pelvis (os coxae) is formed by the fused ilium, ischium, and pubis. It has three reliable sex-related landmarks. In a study of 38 dried feline pelvic bones, the caudal ventral iliac spine separated males from females with 94.4% accuracy, and the angle of the ischiatic arch reached 74.3% accuracy [3]. A discriminant equation built from pelvic measurements reached 97.3% accuracy for sex determination, while a mandible-based equation reached only 64.9% [3].

The pelvis is a common fracture site. In the 80-cat trauma study, pubic fractures were strongly associated with ipsilateral ischial fractures [7]. Left and right sacroiliac luxations were also positively associated with each other, and sacroiliac luxation was associated with contralateral iliac fracture [7].

Femur and Stifle

The femur is the thigh bone. Its head fits into the acetabulum of the pelvis. The patella (kneecap) sits in the trochlear groove at the distal end of the femur. The stifle joint, equivalent to the human knee, is a hinge between the femur and tibia.

The stifle contains a structure called the ligamentum mucosum, a band of tissue that tethers the infrapatellar fat pad to the femoral intercondylar notch. A dissection study of 62 cat hindlimbs found the ligamentum mucosum bilaterally in 95.2% of cats [10]. Because it is often omitted from anatomy texts, students sometimes mistake it for the cranial cruciate ligament [10].

Hip and thigh muscle attachment areas differ between felid species. Compared with the clouded leopard, the domestic cat has proportionally larger attachment areas for the gluteus profundus, tensor fasciae latae, and biceps femoris, while the clouded leopard has larger areas for the gluteus medius, rectus femoris, and semitendinosus [11]. These differences reflect different locomotor habits rather than a difference in overall bone shape [11].

Crus (Lower Leg)

The lower leg has two bones. The tibia is the main weight-bearing bone. The fibula is thin and lies lateral to the tibia. Cats have a small sesamoid bone behind the knee called the lateral fabella, which is a useful radiographic landmark.

Pes (Hind Paw)

The hind paw includes the tarsal bones, the metatarsals, and the phalanges. The calcaneus (heel bone) projects backward to form the lever for the Achilles tendon. Cats walk on four toes per hind paw.

Comparative Notes: Cat Versus Dog Skeleton

The cat skeleton differs from the dog skeleton in several practical ways.

The dog's longer muzzle carries more premolars and molars. The cat's shorter jaw concentrates bite force and reduces the number of teeth, which fits a strict carnivorous diet.

Clinical Relevance, Limitations and Common Mistakes

Skeletal anatomy matters in daily veterinary practice for several reasons.

Radiographic landmarks. Goniometry, the measurement of joint angles, relies on palpable bony landmarks. For the forelimb these include the spine of the scapula, the greater tubercle, the caudal aspect of the humeral head, the lateral epicondyle, the craniocaudal midpoint of the distal antebrachium, and the dorsal aspect of the metacarpals [12]. For the hindlimb they include the tuber sacrale and ischiadicum, the greater trochanter, the patella, the lateral fabella, the tibial tubercle, the fibular head, the lateral malleolus, and the dorsal aspect of the metatarsals [12]. Consistent landmark placement is what makes repeated measurements comparable.

Lumbosacral junction width. Dynamic radiography of the lumbosacral junction in 60 healthy cats established reference intervals for junction width. Width was 2.0 ± 0.2 mm in the neutral position, 2.3 ± 0.2 mm in flexion, and 1.7 ± 0.1 mm in extension [13]. These values help clinicians distinguish normal mobility from lumbosacral instability.

Vertebral canal changes with age. Cats older than 10 years showed increased vertebral canal cross-sectional area and perimeter, with decreased circularity at multiple levels, suggesting age-related remodeling [5]. A normal CT in a young cat may not look the same as a normal CT in a senior cat.

Bone tumors. Osteosarcoma is the most common primary bone tumor in cats, though it is usually diagnosed in older animals and rarely metastasizes [14]. A fibroblastic osteosarcoma of the fourth metatarsal bone has been reported in a one-year-old cat, with an aggressive osteolytic lesion and a Codman's triangle periosteal reaction on radiographs [14]. Extraskeletal osteosarcoma of the meninges has also been described in a cat, where local osteolytic destruction of the frontal bone and cribriform plate allowed the tumor to extend outside the skull [15]. These cases show that bone destruction on imaging always deserves a full diagnostic workup.

Common mistakes. Students and clinicians sometimes confuse the ligamentum mucosum with the cranial cruciate ligament in the feline stifle [10]. Another frequent error is assuming that a reduced clavicle means the cat has no clavicle at all. The cat has a small clavicle, but it does not form a bony connection between the scapula and the sternum.

Limitations. Bone counts vary between individual cats, especially in the tail and in sesamoid bones. Imaging findings must always be interpreted alongside the clinical examination. Individual cases need assessment by a veterinarian.

Frequently Asked Questions

How many bones does a cat have?

A cat has roughly 230 to 250 bones. The exact number varies with the number of tail vertebrae and sesamoid bones.

How many vertebrae does a cat have?

A cat has 7 cervical, 13 thoracic, 7 lumbar, 3 sacral, and about 20 to 23 caudal vertebrae, for a total of 50 to 53.

How many ribs does a cat have?

A cat has 13 pairs of ribs, one pair for each thoracic vertebra.

What is the dental formula for a cat?

The permanent dental formula is 2 × (3 incisors, 1 canine, 3 premolars, 1 molar) upper and 2 × (3 incisors, 1 canine, 2 premolars, 1 molar) lower, for 30 teeth. The deciduous formula totals 26 teeth.

Do cats have a clavicle?

Yes, but it is reduced and does not connect the scapula to the sternum. This free-floating arrangement gives the shoulders flexibility.

Why is a cat's spine so flexible?

The cat has seven lumbar vertebrae and up to 23 tail vertebrae, and the vertebral bodies are loosely articulated. This combination allows the spine to arch and twist far more than a dog's.

Are cat claws retractile?

Yes. A dorsal elastic ligament pulls the claw into a sheath when the flexor muscles are relaxed. Dogs cannot retract their claws this way.

How does the cat skeleton differ from a dog skeleton?

Cats have more lumbar and caudal vertebrae, retractile claws, a reduced free-floating clavicle, and 30 adult teeth compared with 42 in dogs. The cat skull is shorter and rounder.

Related Articles

• Bovine Musculoskeletal Anatomy: Axial Skeleton and Joints
• Comparative Anatomy of the Avian Skeleton: Flight and Locomotion
• Equine Hindlimb Anatomy: Bones, Joints, and Ligaments
• Do Frogs Have Bones? Skeletal Anatomy and Pet Care
• Equine Larynx Anatomy and Function in Respiration
• Canine Lymphatic System: Anatomy and Function
• Bones of the Face: Facial Skeleton Anatomy

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